Journal Institution of Locomotive Engineers
Volume 40 (1950)
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Journal No. 213
Kreissig (Paper No. 490)
The design of light-weight rolling stock. 4-49. Disc. 49-91. Bibliography. 46 diagrams.
Author was Chief Engineer Uerdingen und Dusseldorg Carriage Companies. Discussion: W.A. Agnew (50-1);
Stanier (51) took exception to Mr. Agnew's references to the resistance of past C.M.E.s to the introduction of steel passenger stock. He personally had been responsible for the construction of light-weight steel stock in about 1936, and as Mr. Agnew might know, the new Liverpool and Southport stock had saved a considerable amount of weight. He felt bound to say he had been inspired very largely by a statement made by the late Mr. Fairburn, who had claimed that for every ton which Sir William might save on the coach he (Mr. Fairburn) could save ten pounds a year on current.
An effort had been made at Derby to enable them to use light steel sections and all-steel skin stressed construction, but he thought Mr. Agnew had overlooked the fact that the operating department always demanded the type of compartment construction with doors all along the side, and that was a very great handicap to stressed skin construction. If they could have rolling stock such as they had on the tube railways it would be easy, but to design stressed skin stock for ordinary main lines was a problem.
At the same time he was full in agreement with Herr Kreissig when he advocated the reduction of weight in their stock. He did not think they had made sufficient study of the springing of lightweight vehicles, and he was quite sure that it meant very careful analysis of the movements that would take place and the power that was to be transmitted to get the correct springing to put it right, but he certainly did not think it was impossible. About three years previously he had been in Switzerland and had seen some of the new bogies that they were using on their electric locomotives. He had never experienced such good riding over such a curving road and at the speed at which they could take the curves. The bogie was an entirely unconventional type: it had no horn cheeks, it had radius bars and torsion bar control and coil springs on each side of the axlebox, with oil dampers, and it gave the most excellent riding.
Another point in the Author's Paper in which he had been very interested was the reference to the damage to the life of the springs if there was the slightest mark on the surface. One of the big problems facing the railways was how to prevent corrosion between the leaves of a spring. On the old L.M.S. line they had conducted many experiments in using spring leaves that were ground and polished, but after they had been out for a month or so they were corroded between the leaves and were just as bad. He did not know whether the Author could suggest any means of preventing that corrosion from getting in between the leaves. Coil springs, again, had a very much longer life if one could use polished bar and prevent any damage to the surface. On all high-grade motor cars and on many other vehicles, very great pains were taken to get very highly polished springs for both petrol engines and diesel engines, and he thought one of their biggest headaches in running rolling stock would be removed if they could get a much longer life out of their springs.
He did not know whether Herr Kreissig was familiar with the Paper for which he personally had been responsible in 1939, on Light-Weight Passenger Stock, which was a description of a design which had been got out by the L.M.S., largely for the new stock of the Liverpol and Southport line. There they had adopted light pressed centre girders and used very light pressed sections, and they had reduced the weight on the trailer cars by eight or nine tons and on the motor cars by somewhere about seven tons, but they had not gone to the refinements that Herr Kreissig had shown in his Paper, of hollow axles and very nice, light wheels.
W. S. Graff-Baker (Past-President 52-4) found, unexpectedly that he had two persons with whom to join issue. Herr Kreissigi had referred in his Paper to the advantages which had been gained; from the stressed skin construction of aeroplanes in adaptation to rolling stock. In point of fact, London Transport had used strrssed skin construction since a date when there were no aeroplanes. Even the wooden cars which were originally built when the District Railway was electrified had a measure of stressed body construction inasmuch as the bodies up to the waist-rail were cross-braced and, in addition the door pockets to the roof, in such a way as to carry a substanial amount of load over. the centre doorway which was cut into the car. That form of design had been later replaced by a steel car, which was substantially the wooden car with steel substituted for wood, and gradually on the District line a more consistent design had been developed. .
Referring to the remarks made by Sir William Stanier, he wished to join issue with him on his suggestion that it was quite easy to design a Tube car because it had no doorways. In point of fact, the modern Tube car had two 4 ft. 6 in. wide openings cut in the side and into the roof, and those openings came at the point of contraflexure and therefore of maximum shear stress. The earlier cars had a single door in the middle, at the point of maximum bending. He was sure Sir William, on reflection, would not call that easy. With regard to the question of dynamic versus static design he supposed they were stillmost of them#151;designing by static methods but was dynamic design anything more than getting a completely balanced static design, with all the units doing their fair and proper proportion of the work?
E.S. Cox (54-5) noted problems of corrosion and for end loading quoted the Fairburn formula. Added that the passenger capacity and axle load of the original Southport stock was almost excatly same as then recent stock. T.H. Turner (55-6) noted problems of corrosion; L. Lynes (57-8) noted that light alloys are expensive and also commented on the design of wheel centres; Keith Hitchens (58-9) questionned the life expectancy of lightweight rolling stock. J. Koffman (written 59-65); R. St J. Preston and W.H.J. Vernon (written 65-6); R.S. Hall (83-4); G.C. Jackson (84) noted that considerable rouble had been experienced with all-welded bogies; A. Bonnères (85) recorded buckling headstocks; J.F. Thring (85) noted excessive vibration; W.F. Allen (85-6) noted corrosion; H.S. Stubbs (86) spoke about light alloys..
Birmingham 15 December 1949: E.R. Durnford (79-80); V.F. Dittrich (80-4): corrosion of steel Pullman cars and stressed importance of rust-proofing; J.W. Eling Smith (82); S.H. Morris (82); H. Lawton (written 82); P.K. Dewhurst (82-3)
Nock, O.S. (Paper No. 491)
The relationship between signalling and brake power in handling modern traffic. Joint Meeting with Institution of Railway Signal Engineers. Numbered separately.xvii pp.
R. Steadman (95-6) disputed Nock's claim that 80 mph was rarely exceeded on Coronation between York and Darlington.
Cook, K.J. (Paper No.492)
The late G.J. Churchward's locomotive development on the Great Western Railway. 131-71. Disc.: 171-210. + folding plate. 33 illus., 20 diagrs., 4 tables. .
Paper presented at Institution of Macanical Egineers following Thirty Ninth Annual General Meeting on 22 March 1950: the meeting was chaired by W. Cyril Willams . This is the most complete professional source of assembled data on Churchward design. It begins by emphasising that Churchward took over from Dean some excellent locomotives, notably the 80 singles, the standard goods 0-6-0 (especially the most recent 200), and the several 4-4-0 classes and Aberdare 2-6-0s which continued to be constructed under Churchward. The evolution of the standard classes is examined closely. The initial six envisaged in 1903 consisted of the 2-8-0 No. 97; the 4-6-0 No. 98 (the Dean/Churchward 4-6-0 No. 100) is regarded as a protype for this) and the 2-6-2T No. 99, and should have included a 4-6-0 with 5ft 8in driving wheels, but this did not materialise under Churchward. A 4-4-0 (No. 3473) emerged in 1904 and a 4-4-2T (No. 2221) in 1905. All had 18x30in cylinders and 8½ in piston valves. It was originally envisaged that there would be 9ft and 8ft long fireboxes, but the tank engines demanded two smaller fireboxes.
No. 98 incorporated features of American design, notably the cylinders cast in two halves and joined by a cast saddle. This demanded a separate front end which was joined to the normal plate frames at the rear. The boilers featured a tapering barrel, but initially this was restricted to the rear plate. On 4-6-0 No. 171 Albion the boiler pressure was increased to 225 psi. Cook is not very revealing on the purchase of the De Glehn compound 4-4-2s: he described their general dimensions (with the usual absurd Imperial units) and stated how they were tested against No, 171 Albion as converted to a 4-4-2 and that this led to Churchward designing his four-cylinder simples..
In the discussion W.A. Stanier presented some anecdotal material (pp. 171-2) including his observations on Churchward's County class.Stanier said that it was with particular pleasure that he had come to the present meeting to hear a Vice-President, Mr. Cook, tell them something of the work with which he himself had been mixed up to a certain extent during its early history. . Mr. Churchward had come to Swindon the year of his own birth. He had then been Carriage Works Manager and was actively engaged in developing new things. He had developed the Great Western axle box, which was recognized as being one of the axle boxes most free from failure. They had heard about a number of people who had been associated w,lth Churchward but one of the principal people who had worked with him was George Burrowshis son was present at the meeting. He himself, having been in the drawing office at the time, had seen some of his work.
He could, of course; speak at great length about Mr. Churchward, but would confine himself to referring to one or two points only. Mr. Cook had drawn attention to the 4-4-0 "County" class engine. Churchward had built that engine with his tongue in his cheek. He knew the front end was too powerful for the wheel base. This engine was built for working trains on the Shrewsbury and Hereford line, which was a joint line with the L. & N.W., and the L. & N.W. objected at that time to the 4-6-0 "Saint" class working over it. He was not going to be told what he could do by Webb! Therefore Churchward built the "County" which had plenty of power to run the service.
Another matter he wished to speak about was the advent of the French erigine; Churchward had always been very' keen on spotting things that were good. The French engine had an extraordinarily good bogie and almost from the time the French engine. started running until the present time the Great Western bogie had the French spring control on it, as also had a great many L.M.S. bogies. Then there was also the big end for the inside cylinders The big end on the King, Castle, and Coronation" classes, and on a number of other 4-cylinder engines, had a French big end for the inside cylinder. He would like to tell the meeting something of the" old man." After the first world war a deputation had visited Churchward to tell him of their wishes. Churchward had rather an autocratic way and used to tell his people what to do. The leader of the deputation, the district organiser, said, "You know, the time has come when we wish to be asked to do a thing and not ordered to do it." "D- it all, it is time the' old man' retired," he replied. When Churchward retired the workers insisted on making him a presentation. They asked him what he wanted and intimated that he wanted nothing, and on being pressed he said, "A fishing rod." So he was presented with one and at his request the rest of the amount given was devoted to prizes for apprentices who attended the technical college. At the presentation the Chairman of the Works Committee, having spoken in glowing terms of how they admired Churchward, wound up his remarks by saying that he hoped every hair on his head would be a candlelight to glory. Churchward replied, "Well, there will not be many of them." He was as bald as a coot. . . As members probably knew,he himself had served his time under Dean but had worked a11 his active life until 1932 under Churchward. He had a great regard and affection for his memory. As Mr. Cook had said,'" His soul goes marching on" That was true because all his engines, which are still of the most modern type, were built before 1910. Those who had come after Churchward had tried to follow in his steps ever since.
H. Holcroft (pp. 173-82) said that the Author had completely epitomized the principal events of the Churchward era at Swindon and catalogued the product in locomotive stock. In the brief space allotted to a Paper on the subject there was so much which must be omitted, but there was opportunity in discussion to supplement the theme. As one who was fortunate enough to be on the G.W.R. in a period covering those prolific years from 1898 to 1911, he (the speaker) saw all the developments as they took place and was privileged in time to join the circle concerned in their design.
The Author had eulogized Churchwards personality and depth of vision, but words fail to convey the impression which he created by his presence. All those high qualities which distinguish the true English gentleman were inherent in him. More than anything else it was as a tactful administrator and a leader of men that he excelled. He collected round about him by careful selection a technical staff of diversified talents, many of them having attained high academic distinctions. These he inspired with enthusiasm and drew from them their best, much as. a conductor does from his well-trained orchestra.
Churchward cast his net wide and had his scouts out to spot likely recruits to fill any vacancies. Himself a Newton Abbot man, he did not confine the catchment area to Swindon, but spread it over the entire G.W.R. system. It was excellent team work that contributed so much to his success, and he saw to it that there was always a succession of suitable men climbing the steps to the higher positions and ready trained to step into a place when it fell vacant. The whole organization ran like a well-oiled machine.
When some scheme was to be put in hand, Churchward would issue general directions to the Chief Draughtsman as to what he wanted done. As soon as the draughtsman detailed to carry out the scheme had something to show, Churchward would come along and settle himself on the high stool in front of the drawing board, surrounded by the Chief and Assistant Chief Draughtsman, the chargeman of the particular gang and the draughtsman himself. He would then go into everything in detail. If any question of shop practice or manufacture arose the foreman concerned would be sent for to give his views, or an official of the running department would be summoned to express an opinion on questions of operation or maintenance. Churchward might say, What do the other railways do in this matter, or the Americans, or the French? In a matter of a minute or two, bound volumes of technical publications or textbooks giving the information would be forthcoming from the Record Office through a highly efficient card indexing system. His grasp and discernment were extraordinary, and when he had viewed the subject in all its aspects and had heard what those about him had to say, Churchward would by a process of logic and sound sense come to some clear-cut decision. There was always an air of finality about it and one felt completely satisfied that the right solution had been reached. It was a positive delight to work for such a man. His method might be described in modem parlance as that of the working party, of which he was the chairman.
The Paper is an historical one and it is necessary to recall that the G.W.R. have had a succession of their own men to head the locomotive department, virtually a dynasty. What is more, the mechanical and running departments have had the advantage of being controlled by this one head. In consequence, practice has been continuous in a slowly changing evolution, with tradition a strongly marked feature. The G.W.R. had never experienced the shock suffered by smaller railways in having a C.M.E. from another line, a new broom who ruthlessly swept away their most treasured characteristics and traditions, and inflicted on a long-suffering running department the designs which he thought they ought to be given, complete with troublesome and unwanted gadgets.
Much of Churchwards practice was traditional to the G.W.R., the domeless boiler was a reversion to earlier times, the provision of ample boiler capacity existed in Goochs broad gauge engines, and Armstrong always gave the standard gauge engines boilers 10 per cent. more heating surface than others considered necessary for the size of the cylinder. Standardization of parts and boilers had existed in Swindon-built engines from the first, and was strongly marked in a number of classes in Armstrongs day. In Deans later times the Bulldogs, Atbaras and Aberdares had many parts in common. Much of this standardization had been, however, spontaneous and rather haphazard. What was novel in Churchwards methods had been the projection of a number of standard types in an orderly, well-planned manner, and the setting up of a definite programme of construction based on it.
The Author mentioned the battle of the gauges as a stumbling block to progress. This battle was virtually over in 1872, and only the Paddington-Penzance broad gauge trains had lingered on for another 20 years. Even here, the third rail had been laid in as far west as Exeter for standard gauge traffic. The abolition in 1892 had left a legacy in the form of hundreds of miles of track with longitudinal sleepers and bridge rails. All this had to be relaid with transverse sleepers and heavy bull-head rails before more powerful locomotives could run, a matter of some years work. Traffic development was hindered by the compulsory 10-minute stop at Swindon in connection with the refreshment room contract. No less than £100,000 was paid in compensation in 1895 to end the matter. After that came an era of development, the direct lines to the West, to South Wales and to Birmingham.
As far as locomotive power was concerned, it was then ripe for development to match, although Deans standard goods, the 2301 class, was as good as any in the country, and as far as his 7 ft. 8 in. single wheelers were concerned one could recall how No. 3065 Duke of Connaught, had hooked on to an Ocean Mail train at Bristol and had run to Paddington in under 100 minutes, notwithstanding a severe speed restriction over the Cricklade Road bridge at Swindon. After there, a speed of 80 m.p.h. was maintained for 70 miles on end, a performance difficult to beat.
What Churchward had done was to raise G.W.R. locomotives at one stroke to a plane such that it had taken 25 years for other railways to reach, and his engines had had a useful life of service of at least 45 years. It was a case of history repeating itself, for the broad engines of Gooch produced in 1848 were so much in advance of their day that it was about 25 years before their performance was challenged by the Great Northern single wheelers in the seventies, and they had lasted till the final abolition of the broad gauge, some 45 years.
The interregnum, those years in which Dean was gradually relaxing his hold and giving Churchward an ever-increasing authority, are of intense interest to historians. Feelers had been put out in many directions in an era of experimental design. Churchwards hand could be traced at first in the boilers and his predilection for American practice, and the paper which he read before the Institution of Mechanical Enginers in 1906 on Large Locomotive Boilers was evidence of his deep study of the problem.
The earliest to disturb the typical Dean practice was No. 36, a 4-6-0 with 4 ft. 6 in. wheels and 20 x 24 in. cylinders, built in 1896. It had a wide firebox carried above the frames. The Duke of Cornwall class of 1895 was of typical G.W.R. practice, a 4-4-0 type with 5 ft. 8 in. wheels, but having a large extended smokebox containing spark netting on the American plan, as a distinguishing feature. Next, the Badminton class, a 4-4-0 type with 6 ft. 8½ in. wheels and a Belpaire firebox. One of these, Waterford, received a domeless boiler with raised Belpaire firebox, but that was not as astonishing as Another, the Earl Cawdor, which appeared with a boiler having a flush round topped firebox, a barrel of enormous diameter capped by a diminutive dome. The barrel was filled with a great number of small tubes, the firebox was deep and carried between the coupled axles, with sacrifice of grate area thereby. This sudden change of practice bewildered the uninitiated, but the explanation was that Churchward was not the promoter of the design, which was attributed to F. G. Wright, Chief Draughtsman of the time. Apparently he was influenced by the performance of McIntoshs big boiler engines on the Caledonian, and he wanted to go one better. The idea was evidently that a large storage of 176 hot water would act as a reservoir and assist engines on an undulating profile, and he was permitted to try it out.
The Bulldog, a 4-4-0 type, with 5 ft. 8 in. wheels, had a domeless boiler similar to Waterford, and there came in 1897 a development of No. 36, another 4-6-0 with 4 ft. 7½ in. wheels. It had a domeless boiler with a wide firebox having a raised Belpaire top and a combustion chamber in addition. The cylinders were 19 in. x 28 in., and so marked the first move towards a long piston stroke. A large sandbox straddled the boiler barrel, American fashion, and this engine, which was dubbed Kruger, was followed closely by another having a pony truck of American type in place of the bogie. The 2-6-0 was known as Mrs. Kruger, and she had eight daughters.
Five years later, at the very end of Deans tenure of office, appeared a 4-6-0 with 6 ft. 8 in. wheels. Hitherto all the engines under review had been of the double frame variety with outside cranks for the coupling rods, with the exception of the double-ender 2-4-2 type passenger tanks, of which No. 11 was the prototype. The new engine had inside frames and outside cylinders and the predeliction for things American was reflected in the high side platforms with cab perched on them, and a Stephenson valve gear with rocker. Its angular lines shocked the aesthetes. What lay behind the radical change? He attributed it to failure of crank axles in the Krugers, with their 14-in. throw, and the impression thereby created that crank axles of more than 13-in. throw could not be depended on. In fact, all the Krugers were soon rebuilt in line with the 2-6-0 Aberdare goods with 26-in. stroke. Faced with this apparent limitation, outside cylinders had been adopted to eliminate the crank axle and enable long piston stroke to be adopted without risk of failure.
From this point the standard engine classes had developed, and it would be noted that in all cases from 1895 onwards where there was any new design projected a prototype had been first built before the batch was put in hand if it proved satisfactory. Otherwise, the design was modified or rejected. Progress had been safe and sound, each step being consolidated first. In his table of Standard Classes, the Author had omitted the 2-6-2 T, with 4 ft. 1½ in. wheels, although there were 11 of these engines. No. 115 was the prototype, and the 10 which followed were-perhaps the earliest of the standard types to be built as a batch. They were constructed at the Wolverhampton shops during his (the speakers) time there, and were followed by 10 or 20 identical engines but with 4 ft. 7½ in. wheels, which were classed in the Paper amongst the standard types.
Yet the Author included the County and County Tanks classes in his table, both of which had had comparatively short lives and have not been perpetuated as standards. It seemed to him that all three classes should be treated on the same basis. In the standard classes the 18 in. x 30 in. cylinders were applied to all diameters of wheels, but with the 4 ft. 7½ in. wheel the cylinders would barely clear the more restricted part of the loading gauge. Churchward had certain inhibitions which one came to know, and one of these was a strong aversion to inclined outside cylinders. To keep the cylinders horizontal and lift them clear, the cylinder centre line was raised 24 ins. above the axle centre, so making allowance for tyre and axle wear. As the valve gear and motion was standard to all classes, this offset appeared throughout and without detriment to the working.
The forward extension of the framing, in the form of slab frames to suit the cylinder design, was satisfactory enough with the larger wheeled engines, where the axis of the slab was nearly in line with the buffer centre, but in the small wheeled engines this framing had a downward set to pass below the cylinders and these frames did not stand up to heavy buffing shocks, so that stays had to be provided between the buffer beam and smokebox saddle. Incidentally, the 2½-in offset of the cylinders had the effect of reducing the amount of the set-down of the frame necessary to pass below the cylinders. The Author had given 6 per cent. as the clearance volume adopted. This might be a later modification, for his (the speakers) recollection was that experiments which were conducted with varying amounts of clearance gave 8 per cent. as the best all-round figure. It had to be remembered that carbon deposits on piston heads, covers and passages tended to diminish the volume in service.
The small end clearance in the cylinders were rendered possible by the bush type solid big end introduced by Churchward, while the hollow piston with flat ends secured to the piston rod by a tapered screw enabled flat cylinder covers to be adopted.
The de Glehn compounds had been obtained to compare simple and compound working, the advantage being found to lie with the simple engine, but there were points in the French design apart from compounding which were regarded favourably. No. 40 was built as a four-cylinder simple arranged as in the French design to embody these points, and it was completely successful, although as originally built it had fluted coupling rods which caused trouble by buckling. Rectangular section rods which could whip without taking a permanent set had cured the trouble.
While on the subject of compounding, he said it was of interest to note that the subsequent reboilering of the French engines with the Swindon No. 1 superheater boiler greatly improved their performance and they had a much higher peak of horsepower than the simple engines with the same boiler. This peak occurred about 45 m.p.h. with a cutoff in the H.P. cylinders of about 50 per cent., he thought, but that was not of much practical value in engines required to maintain 60 m.p.h., and the simple engines had proved the better all-round performers. It was the old story of lack of flexibility in compound working. Whilst the matter of simple versus compounding was under investigation, the question of type had also to be settled. It was the hey-day of the Atlantic, and a trial on an extended scale had been made by building a number of 4-4-2s and 4-6-0s simultaneously.
The Atlantics had horn gaps cut in the frames to receive trailing coupled wheels, so that they could be readily converted to 4-6-0 type, while the addition of outside frames to the trailing end of the 4-6-0 to take carrying wheels would enable them to be easily converted to 4-4-2. The Atlantics were the freer running, but the 4-6-0s had the advantage of greater adhesion and reliability in adverse conditions. The extended trial was to find out which was the better suited to G.W.R. conditions throughout the year, with the result that the concensus of opinion favoured the 4-6-0.
The success of No. 40 and the decision to adopt the 4-6-0 wheel arrangement resulted in the Star class. The query might be raised, Why build these more expensive engines carrying the same No. 1 boiler when the corresponding two-cylinder 4-4-0 was such an excellent machine? The four-cylinder under full loading could take one coach more at 60 m.p.h., due to its higher mechanical efficiency and the shorter cut-off which was possible. It gave a greatly increased mileage between general repairs and was smoother in running. Only a limited number were built for the principal long-distance trains, the two-cylinder engines being more suited to fast trains with more frequent stops, owing to the higher acceleration obtainable with the Stephenson valve gear.
The predeliction for American practices came to an end with the advent of the de Glehn compounds, and the vogue became French. In particular the French side bearing type of bogie was adopted in place of the American swing link, and existing bogies were converted to that Another effect was the return of the screw reversing gear to the express engines. This gear had been used on the later Bean designs up to and including the Badminton class. After that steam reversers were adopted on the Bulldogs, Aberdares, Atbaras and the 2-4-2 Tanks. The hand lever was adopted on the standard classes, including the 4-6-0s and Atlantics, but from 2911 onwards and the Star class the screw reverser returned, the lever being retained in other classes.
While Churchwards early designs were generally applauded, there was a certain amount of criticism of their austere and angular appearance. A job which gave him (the speaker) much satisfaction was to prepare a sketch showing a more pleasing outline, by bringing the cab sides down to tender platform level, connecting the high and lower parts of the side platforms by graceful curves and making the cab step match up with that of the tender. That was approved and the Saint class, the 2911 lot, were the first to be built to it, followed by the Stars: The 2901 lot and the other earlier 4-6-0s had been altered as they passed through shops and the Atlantics as they had been converted. As all of these conformed to No. 2911 the whole became known as the Saints.
When superheating came along the question of cylinder lubrication arose. Elsewhere mechanical lubricators had been used hitherto, but Churchward, after experience of them on the French engines, would have none of those fiddly little pumps in the bottom of a box but decided that Swindon should have its own robust design. This embodied a cylindrical chamber holding several days supply of oil which was fitted type. with a ram propelled through a fine thread screw actuated by ratchet and worm from the valve rocker. This reservoir lay on the platform above one cylinder and the ram slowly displaced oil which was fed through pipes to valves and cylinder barrels. Two disadvantages were found, that there was no certainty that the oil was equally distributed, and it took an interminable time in the shed to reverse the ram by hand in order to recharge the lubricator. Therefore a special sight-feed displacement lubricator was designed, perhaps the first application of the kind to superheating.
Standard smokebox arrangements had been developed from the formulae recommended by Professor Goss, of Purdue University, U.S.A., as a result of his experiments on a test plant. The blast pipe and chimney proportions resulting from these formulae had been taken a sound basis to start off with, and tests were carried out in service to adjust the apparatus to suit G.W.R. conditions. When the optimum positions had been found with Nos. 1 to 5 boilers, corresponding standard smokeboxes were adopted.
The first piston valves were those in the 2-4-2 Tanks, Nos. 11 and the first batch of the 3601 class. They were solid plug valves with labyrinth grooves cut in the heads in lieu of rings, and they depended for their steam tightness on being a good fit in the liners. In theory they had the minimum of frictional resistance and wear. If a certain amount of live steam leaked past the heads it was less than that consumed in the cylinders in overcoming the friction of slide valves. The heads were cheap to make, the liners were simple in the absence of rings, and good clear initial openings were obtained for steam and exhaust. In practice the clearance found necessary between head and liner to avoid scoring led to a greater steam leakage than at first anticipated and the last batch of the 3601 class reverted to balanced slide valves. He rather thought that some of the Aberdare goods had these piston valves too.
In consequence of that experience, the Standard engines at first had had piston valves with end spring rings of L section and a bull ring between, but when the semi-plug valve subsequently appeared in the U.S.A. about 1907 it was hailed with enthusiasm and at once tried on the G.W.R., and then adopted as standard, for it was virtually a selfadjusting variation of the plug valve as used in the 2-4-2 Tanks, having all the advantages without the drawbacks. In the semi-plug valve, pressure of steam locked the valve rings in close contact with the liners, so that steam leakage was reduced to a minimum. These valves lent themselves to mass production in the machine shop and needed the minimum of attention on the fitting bench. They gave clearer initial openings to steam and exhaust than other types commonly used.
The vacuum brake was adopted on the standard locomotives; hitherto the steam brake had been exclusively used on engines and tenders, and it was powerful enough if somewhat slow in reaching full pressure on the first application. The reason for this complete change dated back to the collision at Slough in 1900 when an express train had collided with another standing in the station. The inquiry disclosed that the brakes were efficient enough as regards deceleration but too slow in reaching full power, and but for the lag the collision might have been averted or minimised in impact. This touched the G.W.R. in a tender spot, for they rather prided themselves on their brakes, with the consequence that G. H. Pearson and others on the carriage side set about experiments with high-speed brakes, dual pipe systems, etc., eventually settling on a quick-acting valve. For his standard engines, Churchward insisted on a high percentage of weight braked, and all carrying wheels except pony trucks had to carry brake blocks. Owing to limitation of space on the bogie, the first cylinder provided was only 11 ins. diameter, and needed a large leverage, with the consequence that the sheds could not cope with the frequent taking up of block wear. Later on a 14-in. cylinder in substitution gave 60 per cent. more power and improved matters, so that the bogie brake remained until Colletts accession. Tests carried out then with and without the bogie brake in action showed that it had no appreciable effect and it was removed as being more bother than it was worth.
At first there was some difficulty with the vacuum brake on engines working heavy coal trains down the Welsh valleys under gravity. The pump released the brake as fast as the driver applied it, pumps got hot and the brake had to be fully released periodically to recharge the reservoir side of the cylinder. The retaining valve was devised to overcome this, the pump being automatically switched over from train pipe to reservoir on application of the brake.
He once witnessed a practical demonstration of the high efficiency of G.W.R. brakes at one of the Bridge Stress Committees trials. There were several other companies engines present, and all had to go two miles back in order to get up speed and cross the bridge under test at 70 m.p.h. Brakes then had to be fully applied to try and avoid passing a level crossing over a busy road. It was noteworthy that the G.W.R. engine was able to pull up in little more than half the distance run by the others.
Various theories have been advanced for the reason for the building of the Great Bear, No. 111, in view of the known severe restrictions which would be imposed on its running. Those which suggested it was created merely as a show piece or to enable the G.W.R. to claim to be the first to produce a Pacific can be dismissed as motives at variance with the designers character. His guess was that this engine was promoted at the instigation of the Board, and had it been an outstanding success and so lifted G.W.R. loco-performance to an even higher level, the directors would have embarked on a bridge strengthening programme and other works to extend the number of routes available. Failing to qualify for this, the Pacific ran out its life in a restricted sphere. The engine had two principal faults, excessive tube length and the adoption of a Webb radial axlebox at the trailing end. The tube length could have been shortened by the adoption of a combustion chamber, but that had been tried out in the Krugers and was out of favour. The difficulty with the radial axlebox was the lubrication between the hubs and axlebox sidefaces, and the entry of dust there from the ashpan. Had a radial truck with outside bearings been used, the result might have been very different. Apparently Churchward preferred to adopt an existing truck, as used in the 2-4-2 tanks rather than create a new design.
As in the Star class, the outside cylinders of the Great Bear overhung the trailing bogie wheels and there was only just sufficient room for side play of the wheel. Under the circumstances, having regard to the longer wheel base, 15 ins. was the maximum cylinder bore permissible, but 16 ins. could have been arranged had the bogie tyre been reduced from 5¾ ins. to 5¼ ins. in width, or the cylinder centres spread by 1 in. Either of these meant departure from standards and Churchward was content with 15 ins. in view of the amount of adhesive weight. Collett adopted 16 ins. in the Castles and Kings, and it would be interesting to know how he arranged it.
It has been whispered that in later years when Churchward was told that Gresley had produced a Pacific, he exclaimed, Whatever did that young man want to build one for, we could have sold him ours !!
From the Authors list of engines built between 1895 and 1910, it would be observed that Deans double-framed engines of the Bulldog, Atbara and Aberdare classes, which had many parts in common, had been perpetuated long after Churchward assumed office in 1902. They had been merely brought up to date by superheating and the conversion of the bogie from suspension type to side-bearing type. This anomaly could be explained by the fact that Churchward had put first things first and had concentrated on standard types for operating the main lines, continuing the building of the older types for lighter lines and secondary services as a stop-gap measure.
Early in 1910, the Chief Draughtsman explained to him (the speaker) that Churchward had completed his programme as far as the main lines were concerned and was now turning his attention to the secondary lines. He did not wish to build any more of Deans double-framed engines but was going to create a new series of standard engines with interchangeable parts. What he had in mind to start off with were similar types of inside cylinder engines, i.e., 4-4-0 with 6 ft. 8½ in. wheels, 4-4-0 with 5 ft. 8 in. wheels and 2-6-0 with 4 ft. 7½ in. wheels, but with long travel piston valves in place of the balanced slide valves and with inside frames. While it had been just possible to utilize one cylinder design with slide valves in all three types of engines, it was soon evident that limitations of space imposed by smokebox tube plate, bogie and leading coupled axle, made it impossible in the case of large piston valves. The only way out of this dilemma was to telescope the three engine types into one, so leading to a 2-6-0 with 5 ft. 8 in. wheels as a compromise. Churchward came along and weighed up the position, but reached no decision, going off to think things over. He returned the next day, or shortly after, to say, We will have a 2-6-0 with 5ft. 8 in. wheels, but use the 18 in. x 30 in. outside cylinders, the No. 4 boiler, and work in all the standard parts possible. In a matter of a few days the scheme was completed, few new drawings were required so it was possible to place an order on the shops at once for 10 engines and requisition the material. In 1911 No. 4301 appeared, closely followed by the other nine. The running department soon discovered that they had a general utility engine with high route availability, capable of hauling heavy freight trains or running in passenger service up to 70 m.p.h. They found, however, that brake blocks needed taking up rather frequently and the arrangement of pipes below footplate was somewhat congested. Beginning with No. 4311, the trailing end was lengthened by 6 ins. so enabling two 22-in. brake cylinders to be accommodated in place of two ls-in., and the County class cab was substituted for the Saint class one. With this modification, the class was built by the G.W.R. in hundreds, and in time other railways followed suit. No. 4301 therefore represented a milestone in the progress of the locomotive, for it had inaugurated the vogue for the mixed traffic general utility engine.
With the success of the class evident in 1911, the Chief Draughtsman informed him that Churchward was then satisfied that he had all the standard types necessary to operate the entire G.W.R. system. Henceforth all new construction would be to existing standards, except for any slight modifications to keep the design up to date, and that except perhaps for an odd engine or two of special type no new designs would be undertaken at Swindon for another 15 or 20 years. This frank exposition was very considerately given to him to enable him to shape his future course of action, and when the chance came he joined that little party of Swindon men, headed by G. H. Pearson, who migrated to Ashford in 1914, carrying along with them the ideals of Churchward. It was like a band of missionaries setting out to enlighten the heathen and they all knew with what results ! !
While this was largely a personal matter, his purpose in mentioning it was to reveal exactly how the situation regarding new construction was officially viewed at Swindon in 1911. Things turned out very much as predicted. It was nearly 10 years before an odd engine, the 2-8-0 type No. 4700, appeared as the swan song of the regime.
R.C. Bond (182-4) speaking as one who had not had the advantage of early association with Churchward, said that he nevertheless desired to pay tribute to the' outstanding work which he had done in the field of steam locomotive engineering. It was interesting to reflect upon which, among the many influences which Churchward's work has had on contemporary locomotive design, stands out above all others. Three series of locomotive interchange trials are not without interest in this connection. There was first the test in 1910 between two G.W. 4-6-0 Star class locomotives and two L.N.W. 4-6-0 Experiment class locomotives. These trials undoubtedly influenced the design of Bowen Cooke's Claughton class express locomotives, although it seems clear that in this case the lessons which could have been learned were not fully absorbed.
Very different was the case with the later celebrated exchanges in 1925 between L.N.E.R. Pacific 4474- Victor Wild" and G.W.R. 4-6-0, 4079 Pendennis Castle, following upon which the short travel valve gears, hitherto standard on the L.N.E.R. "Pacifics," were abandoned in favour of long lap valves and re-designed gear which so improved the performance of these locomotives. And again in 1926 a G.W. Castle class locomotive, No. 5000, was loaned to the L.M.S.R. and run for some five weeks between Euston, Crewe and Carlisle. The design of the world famous Royal Scot, 4-6-0 locomotive of the L.M.S. which appeared in 1927, was greatly influenced by the performance some months earlier of the G.W. locomotive. Long travel valves were, of course, adopted.
It might be inferred from the foregoing that in the long travel valve gear and the design of the front end lies the key to the outstanding performance of Swindon locomotives. This is undoubtedly true, but in the speaker's judgment the matter goes deeper than this and it is the work that Churchward did on the locomotive boiler that his greatest contribution is found.
Certain features in the design of the firebox staying introduced to the L.M.S. with the Royal Scots were not unfamiliar at Swindon. But in the design of the boiler with which these locomotives were fitted when they were built in 1927, the essential features of the shape of the firebox and water spaces had been missed. It was not until Sir William Stanier introduced on the locomotives he designed as Chief Mechanical Engineer of the L.M.S., the Swindon boiler in all its essentials, that the full benefits of Churchwards work was felt. The maintenance record of all Stanier 's boilers has been outstanding and he would be the first to acknowledge their design as fundamentally based on Churchward's earlier work. He felt satisfied from his experience with the original Royal Scot and 5X 4-6-0 boilers, and those with which these engines have subsequently been fitted, that the shape of the firebox and design of the water spaces are primarily responsible for their high performance and the long life of the firebox plates.
As a matter of interest he had looked up the Paper on Large Locomotive Boilers read to the Institution of Mechanical Engineers by Churchward in 1906. Therein Churchward states that in his standard boilers provision for adequate circulation to the water spaces, and also upwards between the tubes at the firebox tube plate, had been made by leaving space between the tubes and barrel from top to bottom of a sectional area equal to the combined area of the vertical spaces between the tubes at all points, with a balance to ensure adequate feed to the water spaces of the firebox. Freedom from plate wastage and tube and stay trouble was thus ensured.
It seemed clear from Cook's Paper that a guiding principle followed by Churchward is the old maxim that "If it is not necessary to alter a thing, it is necessary not to alter it." Features of design proved sound in practice were left alone and have remained unaltered for many years.
There comes a time, of course, when change becomes essential. Nevertheless Churchward's work would exert its influence on Locomotive Engineers in this country for many years to come, in fact, for so examined the influence of Swindon policy on the design of the Royal Scot class, but It was not until Sir William Stanier introduced on the locomotives he designed as Chief Mechanical Engineer of the L.M.S., the Swindon boiler in all its essentials, that the full benefits of Churchward's work was felt. The maintenance record of all Stanier's boilers has been outstanding and he would be the first to acknowledge their design as fundamentally based on Churchward's earlier work. He felt satisfied from his experience with the original Royal Scot and 5X 4-6-0 boilers, and those with which these engines have subsequently been fitted, that the shape of the firebox and design of the water spaces are primarily responsible for their high performance and the long life of the firebox plates. . As a matter of interest he had looked up the Paper on "Large Locomotive Boilers" read to the Institution of Mechanical Engineers by Churchward in 1906. Therein Churchward states that in his standard boilers provision for adequate circulation to the water spaces, and also upwards between the tubes at the firebox tube plate, had been made by leaving space between the tubes and barrel from top to bottom of a sectional area equal to the combined area of the vertical spaces between the tubes at all points, with a balance to ensure adequate feed to the water spaces of the firebox. Freedom from plate wastage and tube and stay trouble was thus ensured.
O.S. Nock (written 184-5); H.M. Le Fleming (written 185)
Manchester 31 March 1950: Fifth Ordinary General
Meeting of the Manchester Centre was held at the College of Technology on
Friday 31 March 1950 at 6.30 p.m., the Chair being taken by Mr. G.C. Marsh.
Discussion: The Chairman said they were greatly indebted to the Author for such an interesting Paper. He had listened to the Paper himself with particular pleasure, as he happened to be a West Country man, and in consequence had always had a great admiration for all things Great Western from his earliest days. The Author had referred to the Church ward vacuum brake system running at 25-in. vacuum, and also to the working of long fitted goods trains with locomotives of the 2-8-0 class. He thought that the Author mentioned trains of 70 wagons. At what vacuum would such trains be run? The Author replied to the Chairman that Great Western vacuum- fitted freight trains operated at the standard 25 ins., but it was not their practice for the tram to be braked throughout. It was laid down that one-third of the vehicles must be completely vacuum-fitted and marshalled at the front of the train. Concerning superheater flues, these were screwed into the firebox tubeplates, '11 threads per inch, expanded and beaded. He could not say definitely that this practice obtained from the first superheated boiler, but certainly very early in the development of superheating.
I.C. Forsyth (187) said that the main thing that struck him about that review of Churchward was the great influence that was brought to bear on the design of L.M.S. engines by Mr. Stanier's transfer from the Western to the L.M. Region, and in listening to a review of that sort, it was almost like listening to a review of the introductions on the L.M.S. from Sir William Stanier's arrival. Wider bearings for axle boxes and such things were obvious things to them at the present time. The top feed which had been mentioned they accepted as quite the normal way of putting the water into the boiler. They had not quite agreed upon the superheating, because they went in for a greater degree of super- heat and higher temperatures. But the thing that had impressed him most was that whilst the dates were 1903, 1910, 1895, when they looked at the photographs they looked at engines they saw at the present time, with very little difference. They were greatly indebted to the Author for giving them that survey, and he knew that everyone who listened to that talk would appreciate his review very much. He would like to ask the Author how the large smoke tubes were secured in the firebox tubeplate in the Churchward era.
J.J. Finlayson (188) observed how :the Great Western had been the first railway to develop taper barrel boilers and later taper fireboxes. These boxes appeared to become more and more tapered in their length, which in turn caused varying curves on the firebox side, which must have resulted in more difficult boiler making. Churchward was presumably making a very scientifically designed boiler to encourage heat transfer from the fire and quicker water circulation, but on the other hand this appears to necessitate difficult boiler plating. In asking the question from Great Western men as to how they got on with steel stays, he had always been informed that on the Great Western Railway there had never been any trouble with broken steel stays. This is not true of boilers on other railways. Would he be correct in saying that Churchward had succeeded in making a boiler which. from a practical boilermaker's point of view was a difficult thing to make but that the resultant article was scientifically designed from a water circulation and heat transference point of view? Would it also be correct to say that in designing various curvatures of the wrapper plate sides he had succeeded in making a boiler in which steel stays gave no trouble in service?;
Replying to Mr. Finlayson, Mr. Cook said that the development of the tapering boiler and firebox plates did appear to be much more exacting than parallel boilers, but if the project were tackled the diffi- culties could be smoothed out. He did not think they would ever claim that they experienced no breakage of steel stays, but they would clairr. very definitely that the general results were extremely satisfactory. He Would put that down mainly to the development of the curvature of the side plates. Churchward spent a lot of,time in developing these curves. There were several contributory details. In the design of his boiler, particularly the second boiler (on engine No. 171), he narrowed the back. end and increased the throat, and he was particularly keen in providing an area which would enable a very free flow of the relatively colder water into the firebox waterways. There were cases where different waters would affect steel stays differently, but on the whole the results had been excellent. In 1941, he, the Author, had taken a standard 8 boiler off a "Castle" class which was built in 1934. It had run 414,000 miles, and all the original steel stays were intact. The followrng year, he had taken a standard 12 ("King" class at 250 lb. pressure) off after 441,000 miles. When they had built their ubiquitous 0-6-0 tank (57xx class), of which they had nearly 1,000, they had increased the. pressure of the relatively straight-sided boiler from 180 to 200 Ib., and in certain cases they had encountered trouble with the steel stays. It had been necessary to increase the sweep of the side plates.
D. Patrick (188) commented on the statement which had been made about the freedom from failure of firebox stays. In comparison with the practice on other railways, the stays :were of relatively small diameter, but there was another point which occurred to him which was connected with the feed system. He believed that the Great Western Railway were the pioneers of the Top Feed system and they employed a somewhat elaborate system of feed trays which might possibly be the secret of success for Top Feed. In modem times on many railways abroad, in particular, they found locomotives with a Top Feed system in which the water entered the boiler through a twin nozzle or sometimes a pipe, without trays. There was nothing to show that such a system was in any way superior, to side clackboxes from a maintenance point of view on the boiler. He would like to ask the Author whether he con- sidered that the employment of the Churchward Top Feed Tray system was a contributory factor in the freedom from stay leakage obtained.
It also appeared to him to be worthy of note that the Great Western many years ago were using a boiler pressure very much higher than any contemporary railway outside the U.S.A.
The final comment he would make was on the continued faithfulness to inside valve gear. He believed there were now some Great Western engines with outside Walschaerts valve gear, but there were a great many engines having various forms of Stephenson or Walschaerts inside valve gear. Was that system maintained for the appearance and finish of the locomotive, in neglect of the fact that accessibilily must be somewhat difficult for lubrication and inspection, particularly on the tank engines?
!n reply Mr. Cook said that the top feed trays provided a very interesting subject. Since reading the Paper in London, he had had a commumcation which had opened up to him. rather a new viewpoint, and Mr. Patnck had touched on it very strongly. There probably was a great deal in the contribution of the top feed tray towards the general condition of the boiler, It might give a clue to the reasons why they had obtained, such excellent results without complete water treatment. The chemists view generally was that softening must be pursued to reduce hardness to zero or not introduced at all. He could not help recalling the results they had obtained just before the war [WW2] when they got extraordinary boiler lives. In those days shed mamtenance. was, of .course, at its best, but it might be that diffusion and the partial softening effect of heating and splitting up the feed water in the tray was a very valuable factor in the subject of water treatment.
It was correct that Churchward went higher than most people in boiler pressure. Some people thought he went too high: Mr. Cook, however, thought Churchward had a very good reason. It could be argued that from the economical viewpoint there was no value in a hlgher pressure than 180 lb., but the great virtue of a steam locomotive was its flexlblhty and the availabIhty of extra power at a slight sacrifice of theoretical efficiency provided true economy in the railway sense.
He would say that the inside valve gear was for two purposes. One was the fact that Mr. Churchward preferred to keep his outside as plain as possible, but in referring to inside valve gear on Great Western engines, the term must be regarded generally as synonymous with Stephenson gear. It was quite fallacious to assume that valve events of Stephenson gear must be inferior to those of Walschaert gear. The Stephenson gear between the frames on that line gave really good valve events, and they would say that they stood by it on its merits rather than on any particular aesthetic value or the fact that it was tucked away. He had written a short article in the Railway Gazette some years ago m which he had pointed out that the "Hall" class valve gear had only one piece of its gear marked off. This was a check marking of the bore of the twin eccentric sheaves, and all the rest was produced entirely in jigs. He would also refer to the 2900 class engine which was fitted with poppet valves, the results of which were inferior to those of the Stephenson gear.
E.G. Smith (188) asked whether it was the Author's experience that inside valve liners wear far less than outside valve liners on the 4-cylinder engine. He had found it so on the L.M. Region. Replying to Mr. Smith, Mr. Cook said that on ·the matter of the wear of steam chest liners, there was not much difference between inside and outside, but he considered that on the whole wear was greater on the inside liners.
Metcalfe (189) asked if much scale was deposited in the trays. Also, what general type of water did they get on the Great Western, and how did the hardness of the water affect the deposit of scale? There were many different types of clackboxes, some of which appeared to cause some trouble in sticking open when the injectors were shut off. Some companies employed a ball in a cage, others had different designs of valves. He asked what was used on the Great Western. In reply . Cook said. that.it was correct that a good deal of scale-forming matter was deposited in the trays, and that was one of the objects of the tray. The water on the Western Region varied considerably. In a number of cases where trouble had occurred, they had gradually changed the source and obtained wherever possible an improved type of water, but It vaned very considerably, and perhaps on certain routes they benefited from different waters blending with each other. Originally the clacks were ball valves, but in recent years they had been superseded by a double faced shuttle valve mounted in a cage as a renewable unit.
K.R.M. Cameron (189) said that it was regrettable that the locomotive world had for too long been kept somewhat in the dark as to details of locomotive design during the past fifty years on the Great Western Railway, and it was refreshing to see this evening that Mr. Churchward's designs had been so distinctive and yet so up to date even by present-day standards. He could support Mr. Forsyth when he had remarked that some of the drawings they had seen this evening could have their dates changed to 1938, and to all intents and purposes they would be looking at modem drawings. There was no doubt that Mr. Churchward had developed certain ideas along lines different from anybody else, but there was not the slightest doubt that these ideas had proved to be outstandingly successful.
He had always wondered why the G.W.R. did not see eye-to-eye with the other railways on the subject of mechanical lubrication to axle-boxes. Was it a fact that all the axlebox lubrication even. on the biggest and fastest engines, was entirely by trimming feed, or were there any classes fitted with mechanical lubricators? If trimming feed was the rule, were they prone to have hot boxes, or did they enjoy comparative immunity from this trouble?
He had also noticed in a number of the photographs of the smaller wheeled classes of engines, that the centre line of the cylinders did not appear to pass through the centre of the 'driving wheel but was an appreciable amount above it. Was this a general practice, and did it lead to rough riding?
Replying Cook said that there were no engines of Great Western design running with mechanical lubricatIon to axle-boxes. Great Western axleboxes were fitted with trimming feeds from oil boxes on the frame or above it with four feeds, two through spigots to allow for the movement of the axlebox to feed into the two oil holes at 45° each side of the centre of the crown and the two other oil feeds through the horn block to lubricate the faces. That was very satisfactory. The disadvantage was that the keep, which had a worsted pad, was to a certain extent open and liable to accumulate water. The boxes had in recent years been modified by closing the keep except for felt pads in the centre which wiped the journal, and similar felt pads to horn faces. The trimming feeds were eliminated and substituted by oil filler pipes.
The 18-in. x 30-in. engines with wheels smaller than 6 ft. had the cylinder centre 2½ inches above the driving wheel centre. Churchward adopted this in order to raise the maximum Wld~h over cylinders and to avoid inclined cylinders. It was not considered that this adversely affected the riding qualities of. the engines. The early 6 ft. 8½ in. engines had the cylinder centre 2½ rnches above the wheel centre, but all these engines now have them on the axle centre line.
Meeting in Derby 13 April 1950: M.A. Henstock (194-5) noted that Churchward had decided that double admission valves were inefficient and opted for large diameter piston valves.and was surprised that Cook had stressed valve travel rather than lead (which Henstock considered to be a very important factor in smooth running: Replying Cook stated that the reference to lead and valve travel must be taken relatively and to emphasise the importance which Churchward placed upon long valve travel. It should also be borne in mind that Walschaert and Stephenson valve gears have different lead characteristics) but both can be developed to give excellent results. The leads as quoted in the Paper remain the same to-day on the Churchward engines. On the Castles the lead has been increased from the 1/8 in of the Stars to 3/16 in. Henstock also queried the function of top feed trays and was informed. by Cook that they may have made a greater contribution to the condition of feed water than was really planned. Certainly around about 1939, admitting that shed boiler maintenance was at its best, really excellent boiler life was being obtained on the Great Western Railway, such that the chemists would say could only be obtained from fully softened water, but softening was not universal. Main line passenger engines were in many cases running three hundred thousand and four hundred thousand miles between boiler lifts.
E.A. Langridge (196-7) noted how
Churchward had introduced high boiler pressures (225 lb) and stuck with them
unlike other locomotive engineers: he considered that was indicative of excellent
workshop practice and the ability to maintain firebox stays and tubes. He
queried the cylinder layout of the four-cylinder locomotives: on other railways
this layout had been tried but dropped due to the loosening of the cylinders.
In reply the Author said one had to decide in a 4-cylinder design whether
to set cylinders in transverse line or staggered as in the Churchward
arrangement. There were pros and cons; Churchward chose that arrangement
very largely, he thought, to keep the connecting..rods the same length and
to distribute the weight. It did give rise to breathing moments and there
was some difficulty in keeping the exhaust joints tight. There was some trouble
with cylinder bolts at that point.
The regulator opening curve was obtained as shown on the diagram provided that free movement of the valves were maintained and for this purpose one feed from the sight feed lubricator led to the regulator valve. The difference in valve opening on the forward and return movements of the regulator handle was, of course, part of the design and the Experimental Section, when recording regulator openings during tests had to be careful to note whether the regulator was moving on the forward or return stroke. Regarding the Deeley gear, he thought the. North Star was first. Deeley published the gear shortly afterwards. There was correspondence between Swindon and Derby, with the result that acknowledgment was made that Swindon was entitled to use the gear.
G.R. Mahy (198) asked why Churchward built both two and four cylinder versions of otherwise identical designs and whether the valve events were established by experiment and was informed that multi-cylinder designs were appropriate for high speed trains and that valve gear was designed by Hawksworth in the drawing office.
York Meeting: 19 April 1950: chaired by J.N. Compton who made some searching comments, notably on p. 203: in developing the King class, the very high tractive effort seemed to have been achieved by reducing the wheel diameter and increasing the stroke, and asked why it was necessary to go to 40,000 lbf tractive effort on what was a high speed passenger locomotive. Cook replied that the power was needed for the exacting services to Wolverhampton and over the severe South Devon banks. Compton then criticised the short stumpy boilers (a result of Churchward's seeking the maximum degree of standardization in throat plates, etc.) which must have led to difficulties on tubing because the shortness of barrels in proportion to gas area must affect the A/S ratio or hydraulic effect. One must have an enormous number of tubes, and that would lead to too much gas area. Cook avoided the specific question and implied that Churchward was seeking the free circulation of water. Compton's observations on the combining valve received a crisp response: The lubricator combining valve was controlled by the operation of the regulator handle. On opening the regulator, the combining valve was lifted which started the flow of oil and it was cut off again by the closing of the regulator without. interfering with the adjusting needles. The second steam supply from the manifold to the combining valve was for the purpose of completing atomization. Lastly he mildly attacked the sacred cow of the brake valve: it was rather similar to other types of combmed steam and vacuum, but embodied only a large ejector. This caused him to think that the Western type ejector must be rather heavy on steam when the locomotive was stationary. The vacuum pump, of course, replaced the small ejector when running. Cook agreed that when the engine was stationary and the vacuum pump was not operating, the large ejector was brought into operation to release the brakes. This is, however, required for relatively short periods. The economy by this system was extremely marked in 1922 when trials were carried out by a Committee on Unification of Brakes.
Carpenter (presumably G.W. pp. 202-3)
refered to the De Glehn compounds, and asked whether,
in view of the widely accepted idea that it was not possible to accommodate
large low-pressure cylinders between the frames of British locomotives without
undesirable reductions in axlebox bearing surfaces, any heating trouble had
been experienced with the French engines, the last two of which had
235/8in. diameter low-pressure cylinders. He also wondered
whether the valve design of the French compounds, which had slide valves,
was less efficient than that of the Churchward 4-6-0s, which had long travel
piston valves, as the thermal efficiency of the compounds was theoretically
higher. Cook replied that he did not consider that there had been any particular
heating problems with the French compounds as the pressure was limited in
the low pressure cylinders. The engines ran well and were efficient, but
did not give a free exhaust when worked heavily. Nevertheless, a drawbar
pull of 2 tons was obtained at 70 mile/h.. Carpenter recalled that the efficiency
of the similar Nord 4-4-2 compounds was greatly increased in later years
when the front end was re-designed and a. multiple jet blast pipe fitted
and queried whether further investigations into compounding had been made
at Swindon following the Marechal trials between otherwise similar, compound
and simple locomotives in 1912 on the PLM Railway. This part failed to illicit
a response. Carpenter also asked whether it was originally intended to fit
the 47xx class No.7 boiler to the "Castle" class engines, as this had had
the same length between tubeplates and a larger diameter? It had occurred
to him that the increased weight of the No.7 boiler as compared with that
actually fitted to the " Castle" class engines, and consequently increased
axle loading, might have been the principal objection to doing this. Cook
agreed that this was so.
J.F. Harrison (204) had never understood why it was necessary to have stay bars from the front buffer beams to the smokebox. Also, why was it that Churchward, who gave so much thought to matters of locomotive design, did not pursue superheating to its logical conclusion? It seemed to him that he failed to take advantage of what other designers were making the best use of and possibly he would have produced even better engines than the "Castle" engines had he furthered superheating. The third point waswhy only one water gauge? He thought it was wrong. Also, many Western Region engines had under the boiler at the front end, some sort of plate support which might not actually carry the boiler, and he would like to know what that was for. The reply (page 206) noted that smoke box struts were fitted on some classes because the extension frames tended to be liable to deformation by rough usage. It did not apply on the 6 ft. 8½ in. wheels, but on the smaller wheeled engines the depth of extension frames immediately in front of the cylinders was restricted. One water gauge, which was. a unit fitting with test cocks on the pillar, had been found to meet all requirements. The motion plate beneath the boiler did not fit against the barrel plate but was a safeguard to support the front end in case of a breakage of an extension frame. The adoption of a low degree of superheat should be regarded as a "Churchwardism," upon which his views, as mentioned in the paper, were quite definite. He appeared to combine the matters of degree of superheat with boiler pressure. He adopted 225 lb. per sq. inch in 1904, which was much in advance of other designers, and in conjunction with this, wanted sufficient superheat to provide dry steam free of condensation in the cylinders. .
Newcastle Meeting 26 April 1950: R.W. Taylor (208) asked about frame fractures and small tenders. Cook gave a smug reply to the latter: the Churchward locomotives were so efficient that the coal and water consumption was low. Later longer trains and larger locomotives demanded 6 tons of coal and 4000 gallons of water. The frames did not suffer greatly from fractures: the 4-cylinder suffered more frequently, but mainly of a "minor nature" at the leading end. On the 2-cylinder type fractures tended to occur within the portion round the coupled wheels, but could be eased by attention to horn bolt spacing. Birkett asked why steel stays at bottom and copper stays at top of firebox and was informed that steel was cheaper and could be of smaller diameter in circulating area. Free entry of water to waterways was of paramount importance in Churchward's eyes.
Journal No. 215
Lund, G.H.K. (Paper No. 493)
Railway breakdown and rerailing equipment. 226-69. Disc. 269-303. Bibliography. 39 illus.
Presented at Institution of Mechanical Engineers at Fifth Ordinary Meeting of 1949/50 Session on 2 March 1950 with W. Cyril Williams in the chair.
Kelbus ramps, jacks, packing, lighting, breakdown cranes (Cowans Sheldon, Cravens and Ransomes & Rapier), Kelbus rail anchors, cooking, protective clothing, French railways, electric locomotives. Includes specific mention of locomotive derailments which occurred near Maryhill, on West Highland line at Inveruglas and on Skinningrove zig-zag. Discussion: Stanier (pp 270-1) mentioned that as an Assistant Divisional Locomotive Superintendent on the GWR: 12 ton cranes were the highest capacity when he first had to deal with problem. Hydraulic jacks had assisted. In 1910 36 ton capacity cranes became available: a Ransomes & Rapier machine at Swindon and a Stothert & Pitt crane at Old Oak Common. In 1927 when in the USA he had come across the Lidgerwood steam winch. Cited earlier paper by John Baker (Paper 310 of Vol. 23. Illustrations of two cranes retrieving locomotive at Inveruglas on West Highland line and another on retrieving No. 2237 on the Skinningrove zigzag..
Discussion: Rudgard (271-2) described how he had re-railed Kirtley double-frame locomotives with 5 ton cranes. He also advocated issuing the men with beer. A.S. Gillitt (272-3) noted that the 10 ton oil jacks used on the Western Division of the LMR were easier to manipulate than the 20 ton type. There was a shortage of breakdown cranes in the British Zone of Germany. He also made observations on the re-railing of cranes. T.C.B. Miller (279-80) noted how the breakdown gang at Stratford used to live in houses adjacent to the depot and would be called out by bells in these houses. In his response to the discussion Lund (page 281) mentioned the difficulties in re-railing articulated rolling stock and the particular difficulty encountered with the C9 locomotives.
The First Ordinary General Meeting of the North Eastern Centre was held at the G. K. Station Hotel, Leeds, on Thursday 11 October 1951 at 6.45 p.m., the Chair being taken by T. Matthewson-Dick. The Minutes of the Meeting held on the 19 April 1951, were read, approved and signed as correct. The Chairman then introduced Mr. G. H. K. Lund who read his Paper entitled Railway Breakdown and Rerailing Equipment see V. 41.
Meeting in Manchester held at the College of Technology on 26 April
1950: J.J. Finlayson in chair
H. Fowler (298) had asked about the arrest of railwaymen and was informed that the French example was also followed in Scotland, perhaps due to the similarity between tne legal systems. He knew for certainty of an Edinburgh driver who, some years ago, was arrested when an accident followed a signal being passed at danger, and he was bailed out. On a more recent occasion, where a driver had ended up on a platform, killing a bookstall attendant, there was talk of arresting him. The District Officer sent him away over the Border into England to his home station and so avoided the arrest, but the police were not at all pleased at the action of the District Officer.
Cameron (298) received a reply: many of the constituent Companies prior to 1923 did have specially built tool vans, but certainly since that date, the conversion of obsolete coaching stock was the usual practice. He had been brought up to believe that all the troubles in the Motive Power Department about the cost of obtaining equipment went back to Sir A. K. Butterworth, of the NER, who had said that the Locomotive Department was a necessary evil. There was much to be said for specialIy built vans and a case could be made out for their additional cost if their draw gear and braking arrangements were such that the crane could be run between them and so save time shunting. The Author thoroughly endorsed Mr. Camerons view regarding the provision of an auxiliary lifting hook. There were very few cranes in this country so fitted, but the large American cranes had as many as three auxiliary hooks. On each occasion on which this Paper had been read, adverse criticism had been made by speakers regarding the weight of equipment. He understood that efforts had been made in the L.M. Region to provide a light jack, but with the material available, without success. The manufacturers of the 35-ton jack weighing only 35 lb. were the Consolidated Pneumatic Tool Company, but they had informed him that these jacks were not manufactured in this country, though negotiations had been going on for some time with their American Company with a view to some arrangement being made.
In reply to Lamb (300), the Author said he had only had experience with the whistle method. He was not aware that the buzzer was used in this country, though it was the practice in France. On American cranes the driver's position was right forward on one side and the man in charge could therefore speak to him with ease. While it was true that various people might be blowing whistles, that was not a common source of trouble, and whistles had the advantage that the men working on the ground knew what and when instructions were being given to the crane driver. No doubt the buzzer had a good deal to recommend it provided there was someone to see that the wander lead did not get caught up.
In reply to Clarke (300), the Author thanked him for his information regarding the 75-ton German Railway crane. The Author remembered some years ago Mr. Oakes, D.L.S.,. Doncaster, telling him, that when he went to take delivery of the first LNER. 45-.ton crane, he was sent by mistake the drawings for a 120-ton crane m which he found references to power house arrangements, and it appeared that. all the blocking and movement of the beams was done by hydraulic rams controlled by the crane driver. Specifications were believed to. have been got out for Sir Nigel Gresley, who had m mind the alternative to a number of 45-ton cranes, namely, to have one very large crane stationed at a central point to cover the whole o.f the LNER. The only disadvantage which he saw in the automatic arrangements was, what happened if it broke down? ....
In reply to Bradley (300), the Author said that instructions existed on parts of the former LNER in Scotland that the crane must be next to the engine. He was not aware of any similar instructions existing elsewhere, but it was customary at many places for them to marshal the crane next to the engine. He did not feel particularly comfortable travelling at high speed in an old :iding van situated betw.een the engine and the crane. At the same time, the advantage of being able to marshal the crane between two vans and so avoid shunting was so great that he felt the cost of suitably constructed vans and draw.gear was justified.
Robertson, A.S. (Paper No. 494)
Trends in electric traction. 304-25. Disc.: 325-36.
The thermal balances of steam and electric traction were compared. Noted the satisfactory nature of the control gear used on the Liverpool to Southport rolling stock. Included AC electrification; the mercury arc rectifier and the Weir Report. Discussion: Hull (328) queried the effect of third rail electrification on ATC. Marshall (332) queried the effect of nose-suspended motors on tyre wear and stated that the heat loss through cylinders was 5.8%
Journal No. 216
Thompson, W.T. (Paper No. 495)
Rolling bearings their contribution to modern rolling stock design. 343-80. Disc.: 381-424.
Paper read at Institution of Mechanical Engineers on 18 January 1950; chaired by W. Cyril Williams, President. Author employed Railway Technical Division, Skefko Ball Bearing Co., Luton. The following abstract appeared in Loco. Rly Carr. Wagon Rev., 1950, 56, 65-7..
It was estimated that the number of such bearings in use on railways in all parts of the world must have been well over one-and-a-half million; in view of the very large contribution made by these bearings to design, and their great advantages from the operating aspect.The author commenced by summarising the most popular types applied to rolling stock and briefly outlined their suitability for certain conditions. The bearings generally employed were:-
1. Single row deep groove ball.
2. Cylindrical roller.
3. Double row rigid ball.
4. Taper roller.
5. Self-aligning ball.
6. Spherical roller.
7. Needle roller.
Dealing with applications to the axles of steam locomotives the opinion was expressed that bearings should be selected which will outlast the wheel and axle sets, especially when the bearings are direct mounted and have a heavy interference fit. The initial outlay on roller bearings will only be justified in terms of long life, which may vary between 500,000 and 2,000,000 miles depending on the class of locomotive; and for express locomotives reaching 120,000 or more miles per annum it is desirable to calculate bearing sizes for a mileage of 2,000,000 at least.
Freedom from hot boxes is a: major consideration in favour of the roller bearing particularly under high speed conditions. Mileages in the region of 60,000 to 70,000 per annum would appear general for British Railways main line locomotives. The introduction of roller bearings, together with other factors contribute towards increased availability. These other factors include the provision of liners of wear resisting alloy steels on the boxes and guides, which will ensure the slackness of bearing and guides remaining fairly constant, giving increased mileages between adjustments of the axlebox guides. The lateral play also remains constant not being dependent on the rubbing faces of wheel boss and axlebox, thus controlled play in the hornways, plus the 360 degrees support given to the axle by the roller bearing will reduce pounding effects on the coupled axles to a minimum, a very important contributory factor to greater efficiency and improved wear and tear of the mechanical parts. The latest high-speed Pacifies on the London Midland Region (British Railways), i.e. Sir Wm. Stanier, F.R.S. and City of Salford, had reached mileages of 118,000 and 106,000 (November 1949) and had not yet been shopped for major overhaul. These mileages were already well in excess of usual permissible mileages between shoppings, and although there are conditioning factors of tyre wear, cylinder valve liners and boiler maintenance to take into account, the roller bearings will, it is hoped, play a. valuable part in increasing the earning capacity of the locomotives by reason of the increased mileage gained between major shoppings. These locomotives are completely roller borne, both spherical and taper roller bearings being used. The leading inside crank axle of these four-cylinder locomotives presented a special problem owing to the limited length of 10 in. available for the axlebox.
Thirty-five 4-6-2 locomotives with bogie tenders, built by the North British Locomotive Co. Ltd. for the Western Australian Government Railways were equipped with spherical roller bearings on all carrying axles and in addition sixteen have coupled axles equipped with a similar box to that used on Sir William Stanier, F.R.S but arranged for top spring loading. The trailing truck, which carried 11 tons, had a feature of special interest (Fig. 1). The radial Cartazzi type boxes were replaced by an auxiliary frame with central lateral control springs, and a self-aligning box is located in the hornway gaps of the rigid frame structure. The radial guides form an integral part of the auxiliary frame which is designed to give a lateral play of 1¼ in. each way, with flat sliding surfaces between the spring and the top of the truck frame. @@@
The New Zealand Government Railways had used roller bearings extensively on locomotives for many years. Their 4-8-2 TA class engines were completely equipped with spherical roller bearings on all locomotive and tender axles. The coupled boxes were of the cannon type. Forty of these engines were built by the North British Locomotive Co. Ltd. and a further thirty-five in New Zealand. Half of the latter are equipped with taper roller bearings throqghout. Of special interest is the decision of the New Zealand Government Railways to tryout roller bearings on the side rods of this class of locomotive. All pins are roller equipped on the trial locomotives, with the exception of the intermediate pins, which have plain floating bushes and serve to stabilise the rod assembly. Extra play can be allowed in the floating bushes. Many special purpose locomotives for heavy marshalling work have been successfully equipped in this way on all side rod positions, and have given full satisfaction, making decided improvements in the wear and tear of mechanical parts by reason of the absence of wear on the pins. For main line locomo- tives a number of successful installations have been carried out on the main driving pins only (i.e. con- necting rod big-ends and coupling rods). The relative differences in the float of the respective axles - ~ill produce a very slight mis-alignment of the rods, but with spherical roller bearings these movements take place with perfect ease and no wear. There has been some hesitation in applying roller bearings to all the pins on main line locomotives owing to the reduction of play between the rod centres. When plain bearing boxes are used with tapered adjustable wedges there is a very great danger of pro-loading the roller bearings on the side rods and of seizures resulting. Furthermore, especially with locomotives without trailing trucks, the close proximity of the fire box to the rear coupled axle can lead to unequal expansion of the frames and rods, which again could induce a heavy pre-load on the trailing side rod bearings. The solutions to these problems were outlined and included stabilising the rods by the provision of side check liners of manganese steel - see Figure 2.
Particulars were given of many locomotives now on order which are to be equipped with spherical roller bearings. These include ten class 5 4-6-0 locomotives to be built at Horwich for the L.M.R. and fitted with these bearings on all engine and tender axles. A further ten will be equipped with such bearings on the driving axles only.
Ease in starting especially eo mm ends the roller bearing for diesel mechanical locomotives and rail cars, and in particular for shunting work. The mountings on inside journals can follow the principle of steam locomotives, although there is no need for the same elaborate protection of the bearings against water and also dust from ashpans. Spherical roller bearings for jackshafts are now commonly employed and as the jackshaft boxes are usually fixed as separate units to the frame plates the ability of the bearings to give initial alignment is an important feature.
The A.E.C. rail cars of the Western Region are completely roller borne. Twenty of these cars are now being built for the Great Northern Railway of Ireland, by the Associated Equipment Co. Ltd. In electric motor coaches and diesel electric, electric and gas turbine locomotives the axle bearings are usually applied to outside journals and the boxes are direct or sleeve mounted. On the equalising type of bogie used on the Dutch State Railways on electric and diesel electric stock the self-aligning box is used. With this box construction the side-spring beam is suspended below the bearings, effecting a controlled pendulum suspension and improved riding qualities. On electric stock with one conductor rail only or with overhead wires, the earth return from the traction circuit is via the axles and wheels to rail. In the normal course of events the current passes through the axlebox bearings. An alternative path is provided on the driven axles by the axle-suspension bearings. Experience throughout the world has shown that no serious troubles arise due to current flowing through the spherical roller bearings in the axleboxes as long as the axle-suspension is carried out with plain bearings. The reason is, of course, that the bulk of the current passes through these plain bearings as they offer the path of lesser resistance. The problem of electrical leakage through the roller bearings does, however, require special con- sideration when the circuit is not bridged by plain bearings, i.e. in the cases where roller bearings are used for the axle-suspension. Similar conditions arise when the motor is carried on the frame and roller bearings are used in the quill-drive. As a rough guide it may be stated that any protection device should prevent potential differences between inner and outer rings exceeding 0.5 volts.
An interesting design, patented by Als-Thom, of Paris, and used on fifty Bo-Bo diesel-electric locomotives for the Tunisian Railways is shown in Figure 3. Guidance of the box is by links centred in silentblocs and pivoted to the frame and axlebox at diagonal locations. These links permit vertical move- ments due to the deflections of the underslung springs, and twisting moments are induced radially which are ressted by the resilience of the silentblocs, The box itself is a stable contruction with twin bearings mounted on withdrawal sleeves.
Reference was made to the wide application of roller bearings on carriages and wagons - the demand for bearings for the latter has been very great of late years. An axlebox design described has bearing sizes selected to give a life of not less than 500,000 miles and the average life expectation will be five times that figure. One filling of grease will suffice for periods of 18 to 24 months.
The paper concluded with a reference to the subject of standardisation. Energetic endeavours have been made in this direction by the Union Internationale des Chemins de fer and the author expressed the opinion that it seemed advisable to standardise on metric dimensions where possible, in view of the greater world demand for metric sizes and taking into account the large potential export business of British manufacturers.
Self-aligning ball bearings were first applied by Gresley to return cranks of Walschaerts link motion on GNR locomotives in 1916. Cited paper No. 317 by P.A. Hyde and report by E.L. Diamond.Lomotives for iron and steel works, Iron & Steel Institute, March 1947 wherein shows advantage of roller bearings on ingot cars. Discussion: C.W. Clarke (382-3) under Indian conditions G. Hally (p. 385) noted that Metropolitan Railway had fitted some trains with roller bearings, once fitted "one could forget about them. J.J. Johnston (p. 387): Drumm battery electric railcar introduced in 1929 had been a success: it had a 21 ton axle load and could attain 55 mph. In 1939 the three Irish Queen class locomotives were fitted and had a 21 ton axle load. K.R.M. Cameron (p. 398) noted that a Royal Scot tender equipped with rolling bearings could be pushed by two foremen in the erecting shop.
Gammon, C.A. (Paper No. 496)
Standardisation and design of goods and mineral wagons as applied to British Railways. 425-65. Disc.: 466-85; 695-709.
Presented at Institution of Mechanical Engineers on 19 April 1950: W. Cyril Willams in Chair. Included an assessment of cast iron versus cast steel for axleboxes; axleguards; bearing springs,; drawgear (rubber springs: steel and rubber versus all rubber); Buffers, brakes. Discussion by E.S. Cox (466-7) noted that Pugson regretted that he could not be present (the absence of Pugson makes Riddles choice of his rolling stock "expert" even more bizarre). Stanier (467-8): When he was on the Great Western Railway, the late Churchward built a 40 ton bogie coal wagon, but he found that the tare of the 40 ton-wagon was greater than the tare of two 20-ton wagons, and it was very restricted in the places it could serve, and so naturally he built 20-ton wagons. On the Cornish Riviera Limited they had measured the quantity of oil placed into the axleboxes, and the sealed boxes were run for eleven months - care was taken to examine the boxes adjacent to the engine to ensure that water had not breached the dust shields. Queried the change to oil-hardened plates from water-hardened: danger of mixing the two. T. Hornbuckle (471-2) that Clayton, Carriage & Wagon Superintendent of the MR had constructed 80,000 wagons to one design at a cost of £65 per wagon. These 8 ton wagons were mass produced at Derby Works. B.C. Bean (702-3) commented on the advantages of bogie stock (and observed that it was better suited to the freight then being carried by road) and on rubber drawbar and buffer springs and their use avoids damage to the headstocks. Discussion Glasgow Meeting 13 December 1950: F.J. Pepper (703) noted the value of rubber springs and the author in his response (p. 708) noted that rubber springs lasted for at least ten and possible fifteen years. See also Simpson: Specially constructed railway wagons (Volume 44 Paper 533)..
Carling, D.R. (Paper No. 497)
Locomotive testing on British Railways. 496-530. Discussion 530-91.
Presented at Institution of Mechanical Engineers on 20 September 1950: R.A. Riddles, President, in Chair. This was a beautifully written paper and surveyed all the testing equipment available at the time: the GWR dynamometer car; the Swindon locomotive testing plant; the ex-North Eastern Railway dynamometer car, and the counter pressure locomotive; the ex-Lancashire & Yorkshire Railway dynamometer car; the LMS gas analysis car (described by P.Lewis-Dale, Institute of Fuel 1936) and the two self-weighing tenders. the "new" LNER dynamometer car fitted with Amsler hydraulic equipment, the "new" LMS dynamometer car and its associated mobile testing unit and special tender. Obviously, the Rugby testing station is also described. On page 521 and Figures 26 and 27 there are details of the famous comparitive tests between a 2301 Dean Goods 0-6-0 with an unmodidied LMS Ivatt class 2 2-6-0. Discussion: Bond (531-3) made reference to Rugby testing station. T. Henry Turner (535-6) noted that Ivatt had read a paper at Doncaster in 1897on the chimneys of locomotive engines in which he had examined chimneys from twenty companies; Cox (536-7) the LMS had borrowed the LNER dynamometer car to calibrate the Crewe and Horwich cars and had noted the accuracy of the LNER dynamometer car, he also observed that the class 5 and 5X "had considerable variety of boiler proportions". A Reidinger (540-3) refered to D49/2 and class 5 45218 (the later being equipped with special piston valves which gave five different values of lead. The author's reply stated that in both cases the steaming rates had been increased. Tuplin (555-6) proposed a circular test track with a two mile diameter.
The Derby meeting on 19 October was chaired by E.R. Durnford (572) who refered to the tests of the Ivatt Class 2 and 4 2-6-0s. C.S. Cocks (573-5) mentioned the Testing Committee, he was interested in the tests on the D49 class locomotive with poppet valves, and had some fairly sharp comments about the draughting on the Ivatt 2-6-0s. the Author (page 577) reported on further trials on the class 2 2-6-0 with the Western Region's dynamometer car, and he had seen a photograph of that little engine attaining the summit of nine miles of 1 in 300 gradient at 40 m.p.h., in 41 per cent. cut-off, with regulator full open and a load of 15 coaches; this was with the existing cylinders but with the revised chimney. Glasgow Meeting on 1 November 1950 chaired by C.D. Hanna: E.D. Trask (585) mentioned the quantity of steam required for steam heating. W.H. MacLeod asked about double blast pipes and on tests with poppet valves on the D49 class. In reply Carling considered that double blast pipes were not required on locomotives of the size of a class 5 and that in the D49 tests something was wrong with the valves or their seats.
K.W. Everett 577) wrote that he understood certain tests had been carried out at Rugby Testing Station in connection with the investigation to determine the dimensions of lead given to the piston valve driven with the Walschaert gear to give the best results and he asked if the Author would relate his findings on this subject and whether these had been in any way conclusive. It is reasonable to believe that there were occasions when a sacrifice of total power had to be made for improved efficiency of running in a machine and the choice of the most suitable setting for the valve events in a locomotive might be made from the best running conditions for the bearings and the best riding conditions of the engine as a vehicle. The effects of rough riding due to a bad choice of valve events may be considerable on maintenance. They were all aware of the kinetic energy of steam and the power which could be developed in the steam turbine from its use and it was quite evident that in a reciprocating steam engine, when the compression pressure was inadequate, an impact of considerable magnitude could be imparted to the piston at admission from those very same conditions. A way to overcome this effect would be to round off the heel of the indicator diagram with a steeper compression curve by adding exhaust lap to the piston valve, and although this would mean a certain sacrifice of power, a reduction would, no doubt, follow in the maintenance due to less hot big ends, broken cylinders, etc., apart from smoother riding conditions and less wear. .
Journal No. 218
Shields, T.H. (Paper No. 498)
The Giffard centenary: a survey of locomotive injector development. 597-649. Disc.: 649-73.
Presented at Institution of Mechanical Engineers on 25 Ocober 1950: R.A. Riddles (President) in Chair.
Paper Number duplicated in Warder paper on electric traction Vol. 41.
Comprehensive review including patents. Began with showing the boiler feed arrangement (pump) for a Caledonian 2-2-2 of the Crewe type on the Caledonian Railway. Then explored the development of jet instruments via Venturi (1797), Nicholson (patent in 1806), the Marquis Mannoury d'Ectot, Benoulli, Euler and Bourdon with patents in 1848 and 1857. Also pre-dating Giffard's invention Andrew Barclay and his draughtsman Alex Morton were working on jet condensers from 1854. Giffard's patent 1665 dated from 23 July 1858 and an extract from it is reproduced on pp. 601-2. Samples of the injectors were supplied to the Paris representatives of Sharp Stewart and R. Stephenson, but only the former successfully asembled the device (aided by John Robinson) and this was fitted with to a ballast locomotive with the assistance of James Cross of the St Helens Railway in 1859, and subsequently to a freight locomotive. Robinson and Cross conducted experiments to establish the effects of temperature and vibration. Ramsbottom fitted an injector to a Problem class 2-2-2 in 1860. Sharp Stewart obtained the British rights and continued to manufacture injectors until the firm moved to Glasgow in 1888. The US rights were obtained by William Sellers of Philadelphia: the device was first fitted to a Baldwin locomotive for the Clarksville & Louisville Railroad in 1860 (incidentally the rapid uptake of Giffard's invention should be of interest to those studying technological innovation). In 1864 Andrew Barclay was involved in litigation concerning infringement of the Giffard patent. The first modifications were patented by Gresham & Robinson (2784/1864) and Gresham (3169/1867)..
Discussion: Cox (651-3) noted that tests were performed on injectors by British Railways (but types were not identified in Paper); Holcroft (653-5): In Maunsell's day on the Southern Railway a special point had been made of the simplicity and reliability of injectors and their accessories. The injectors were located behind the foodsteps to the cab where the cones could be got at without having to uncouple pipes to do so. He entirely disagreed with the Author about his views on the best positions of clacks and injectors.
Glasgow (669-73): The Chairman, C.D. Hanna (669-70) noted the connection between the Robinson family from J. Robinson's 1860 IME paper and the death of C.H. Robinson, a Director of NBL, in 1940; G.W. Phillips (670-1) noted his experience of the exhaust steam injector c1909 with Ivatt Atlantic superheated boilers fitted to Nos. 1452-61.
Riddles, R.A. (Presidential Address)
Nationalisation and the mechanical engineer. 675-94.
Main theme was standardization and some case was made for retaining steam traction. Noted that the Southern Railway and the LNER had Chief Electrical Engineers and that this was not so on GWR and LMS. The table below compares the cost of steam with other forms of motive power.
|type||cost (£k)||starting tractive effort||1 hr DBHP||cost per DBHP|
|1600 hp CC type diesel electric||78||41400||1200||65|
|2500 hp A1A gas turbine||138||33000||2000||69|
|CC electric for Woodhead||37||45000||2120||17|
Noted that standard coaching stock was all-steel, exploited welding, had Buckeye couplers and Pullman gangways which held the train together in the event of accidents. Resistance to end-loading was doubled. Largely evaded the wagon problem except to note the vast intake of private owner wagons many of which were in a very poor stock and had to be scrapped..