Journal Institution Locomotive Engineers
Volume 14 (1924)
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Journal No. 63 (January/February 1924)
Smith, J.H. (Paper No. 153)
Some aspects of corrosion. 9-17. Disc.: 18-29.
Read at Rosnrio, on 14 June 1923: chaired C.F. Ryan. "The subject of corrosion is so vast, vexing and baffling that every engineer and chemist "is up against it" very early in his career, and he evades it, or explains it as best he can, or passes it on to someone else to investigate". A review set against the difficult conditions in Argentina.
Cranmer, H.D. (Paper No. 154)
Petroleum and the application of fuel oil to industry. 32-76. Disc.: 76-113.
Read at Retiro, Argentina on 6 July 1923: chaired by A.W. Bannantyne, CME, BAWR.
Use of fuel oil in forges, furnaces and stationary plants; boiler testing, plant losses, etc. ; burners in general, concluding with use of fuel oil for locomotives.
five advantages of using oil-fired furnaces and forges in preference to coal, and which are:-
1. Decreased fuel consumption;
2. The fire can be shut off or started in a few seconds;
4. A greater amount of work can be turned out in a given time; and
5. The degree of heat is more uniform and can be regulated to any desired temperature.
Anderson, D.S. (Paper No. 155)
The problem of the locomotive condenser. 118-39. Disc.: 140-5.
Thanks W. Pickersgill and Ramsay Condensing Locomotive Company. Considers gain to be achieved through vacuum, the Ljungstrom Air Condenser, the evaporative condenser aand the theory of heat transmission. In theory savings of 40% could be achieved in coal and water consumption. Made refernce to the Ramsay turbo-electric locomotive, illustrated in a "recent issue" of the Railway Gazette (21 September , 1923): line diagram of the locomotive was given there with the axle loads, and the weight of the complete unit was over 154 tons. This was considerably in excess of the weight of a modern passenger engine and tender, an average figure for which was 130 tons.
Attock, F.W. (Paper No. 156)
Locomotive shed lay-out. 147-61. Disc.: 162-74.
The interior turntable type, as the name implies, is laid out with one or more turntables under the roof and with stabling pits radiating from the turntables. This type of shed is comparatively expensive for the stabling accommodation it gives, the roofed area being 100% greater than required to cover the same number of engines in the parallel road type: the Author did not use the term "roundhouse". The main advantage claimed for this type is that the engines can be taken out in any order desired without regard to the order in which they have been put away, and without shunting other engines. On the other hand, this facility is only obtained at the cost of introducing a vulnerable point within the shed, inasmuch as an accident to the turntable may block in large sections of engines with serious consequences to traffic. The parallel dead-end road type is obviously the most economical as regards structure and turntable equipment, and if the length of the shed is limited to not more than six or seven engines to each road, and providing also that forethought is given to the order of stabling the engines, it is found in practice that very little shunting is required.
Records show that at sheds where there is reasonable room for the engines dealt with, shunting for the purpose of liberating engines blocked in at the back does not average more than one instance during twenty-four hours, whilst at congested sheds these movements average six in twenty-four hours.
The parallel road shed, by reason of the small area covered, is also economical in lighting and heating, though the latter consideration is perhaps not of great importance in this country.
The parallel through road type has the same advantage as regards economy of structure as the foregoing type, but is expensive in the road lay-out, the leads to the shed roads being in duplicate to permit departure at the other end of the shed. The advantage claimed for this type of shed is based on the assumption that the engines can go in at one end of the shed and pass through in a more or less continuous stream, undergoing repairs, cleaning, etc., in the shed and passing out at the other end ready for traffic. This principle might be realised if it were possible to standardise repairs and put them on a uniform time basis, but as it is the progress of the engines through the shed must necessarily be restricted to the time occupied on the longest job; moreover, at least one or two of the roads must virtually become " dead ends " in which the heavy repair work can be set aside for an indefinite period.
Dobbie, David. (Paper No. 157)
Some aspects of locomotive running and running shed repairs. 175-92. Disc.: 193-203.
Presented in Glasgow on 29 November 1923: chaired Richard Guest..
With regard to the question of whether the enginemen themselves have progressed during the last century in knowledge at the same rate as the locomotive has progressed in efficiency, the answer must be positive or negative according to the individual man being criticised. That many men now are as efficient as the men of bygone days is indisputable, but it is equally true that through lack of interest and lack of using their opportunities some railway employees have not made good use of their time.
In like manner the lesson to be carried away from our short consideration of running shed repairs is the importance of securing the most efficient and best men to do the work, modernising the equipment both of the locomotive and the running shed and encouraging the men to take an intelligent interest in their work with the object of increasing their efficiency.
Discussion: Chairman (Richard Guest:193-8): When Dugald Drummond succeeded William Adams as locomotive superintendent of the London and South Western Railway, he produced something in the nature of the American principle at Nine Elms, and it turned out to be of the greatest possible value. At that time many firemen displayed a want of knowledge and others possessed only a superficial knowledge; the classes were introduced to combat that sort of thing. I do not know to what extent the railways companies in Great Britain have taken this matter up; but it may be safely said that we, in this country, are still a long way behind our American cousins in this respect.
Journal No. 64
Inaugural address. 206-16
Delivered in Leeds on Friday 16 November 1923 by Chairman of the Centre.
On the LNER the locomotive running department had been separated from the chief mechanical engineer. Some arrangement of this kind appears to he necessary as a result of the Grouping as the old system, under which one officer was rcsponsible for designing the locomotives, rolling stock, and the mechanical appliances, not only in the workshops but in goods warehouses, power stations, dock machinery, etc., and in addition had to organise and control the working of the locomotives, is unsuitable in so large a concern as each of the railways now constituted. This has also been recognised by most other companies, as they have organised their systems somewhat similarly, the LMS having gone further by appointing a separate officer to supervise the carriage and wagon department as well as having separated the locomotive running department from the chief mechanical engineers department; whilst the two rcmaininu companies have made changes in their organisations with the object of relieving the chief .mechanical engineer of some of his former responsibilities.
An interesting innovation the booster. "Why should we continue to build the big engines with a maximum power which is only real1y required for very short sections with steep gradient in journeys covering very long distances, if the use of the booster on the short up-grades will solve the problem? Theoretically, the booster (which is being extensively used in .America) appears to be an ideal arrangement. It remains to be seen whether the boiler capacity, of the less pomerful engines can generate sufficient steam to supply both the booster and the locomotive with a full capacity of steam sufficient to carry them up the heavy grades. Probably more use could be made of the exhaust steam from the locomotive to supply the booster. This question certainly deserves the attention ot our Institution, and here again let me add the Cliict Mechanical Engineer of the London and North- Eastern Railway has been the first in this country to bring thc booster before the notice of the British railway norld. The application of the booste principle should have some really serious thought given to it, as I consider by this means the steam locomotive may possibly be given another lease of life, and the case for electric traction may be put in the background for some considerable time for long distance working.
Spencer, B. (Paper No. 158).
Some features of locomotive design. 216-21. Disc. :221-7.
Presented at Leeds on 16 November 1923. Spencer outlined some design desideratta which included conical boilers (to reduce weight at the front end) and Belpaire fireoxes. The more general adoption of the solid end form of outside connecting rod was a feature worthy of note. The complicated split brass and cottered end had no great advantages over the bushed type, as with modern appliances the renewal of a worn bush was not a difficult matter for shed staff. Although Walschaerts valve gear had been used on Continental Europe for many years, it had only recently been extensively fitted to British locomotives. Compared with the Joy gear, which is difficult to maintain, Walschaerts gear avoids the necessity of drilling a hole in the connecting rod (which had been held responsible for a number of connecting rod breakages.. Being generally applied to the outside of the engine, Walschaerts gear is less liable to neglect, being easily accessible for inspection and lubrication. On the modern locomotive the Stephenson gear is crowded between the frames, and inspection can only be carried out over a pit. Under these circumstances it is not surprising that proper care and attention is not always given. As the eccentric motion of the Walschaerts gear is taken Iiom a small crankpin, the high surface velocities of eccentrics and the consequent lubrication difficulties are eliminated and the use of ball Iiearings made possible.
The removal of the valve gear from the inside to the outside of the frames also facilitates the lateral bracing of the frames. With the Stephenson gear adequate frame staying is extremely difficult, as between the cylinders and the driving axle, where cross bracing is of vital importance, the space is occupied by the gear.
G.A. Musgrave (225-6) presented a defence of the Doncaster traditions. : The author infers that the Belpaire type of boiler was preferablr to the round-topped boiler. It must he admitted each has advantages and disadvantages, but he was of the opinion the round-topped boiler was the more extensively used. In the Belpaire boiler two flat surfaces are more simply stayed than when one is flat and the other round, giving greater flexibility under variable temperatures. The steam and water spaces are greater. It is more expensive to construct aiid adds weight without increasing heating surface. Belpnire boilers had given trouble by cracking of the throat plate in the "ogee "-shaped portion between the upper corners .of the firebox and boiler barrel, but with this exception maintenance is said to bc less than in the round-topped boiler on account of the more equal distribution of stresses. The breakage of stay holts in the upper rows is stated to be less in the Belpaire type than in the round-topped type. The extensive use of thr round-topped type is explained by. the results from it being, on the nhole, satisfactory.. Although the stresses in the plates and stays cannot be determined accurately by calculation, the service of many thousands of these boilers has proved the safety of the type when properly constructed and maintained, and has demonstrated the correctness of such calculations as are made to determine their strength. Referring to the solid bushes for the outside connecting rcds, there is a great deal to be said in their favour. The large end strap with split brasses, cotters and bolts has disadvantages, as each item mentioncd made the cause of a failure on the road. The result of improper fitting and examination may be a broken strap, or the cotter is likely. to be thrown out, the bolts are apt to be broken due t o becoming loose, or the nuts working off, etc. Also a careless workman can easily cause dammage to the cylinder covers by not lining the brasses up properly, and not giving sufficient clearance at the end of the stroke. The disadvantage of the solid buqh is that after a certain amount of wear has taken place it must be renewed.
There appears to be some discredit given to the Walschaerts valve gear, and one of the chief objections appears to be noise. I do not think that is sufficient to condemn the system, but I am of the opinion that the clattering is chiefly from the connecting and coupling rods. .Is Mr. Hird remarked, it is a very satisfactory and economical gear. The port opening and cut-off takes place rapidly, adjustments can easily be made, and the pins can be thoroughly lubricated and examined without difficulty. Enclo4ng this motion with iron plates, as suggested by Mr. Gibbs, would not he conducive to obviating trouble, but on the other hand would tend to create it.
Wickham, R.G. (Paper No. 159)
Drawing office organisation. 241-54. Disc.: 254-9.
Author was graduate from Doncaster, but presented his Paper at Darlington on 23 December 1923. Includes the classification adopted for the storage of drawings.
Considered drawing office library of technical journals and text-books. The leading engineering papers, both locomotive and general, are obtained and circulated for perusal among the chiefs of the various departments. These oficials record for their own information anything that is, or likely to be, of special interest to themselves, and the journals are then handed over to the drawing office to be subsequently bound and retained for reference. Here they are subjected to a thorough examination, and any articles of special importance or interest recorded in an "engineering journals" book.
In order to facilitate the tracing of articles which are naturally various, this book is divided into sections, each dealing with a separate subject. Thus, when it is necessary to consult an article on, say, copper stays, a glance down the firebox section will at once reveal the title, page number, name and date of journal in which the article appears. Since all this information is contained in the index as supplied gratis by the publishers, it might be supposed that in the noting and recording of these things time is wasted and unnecessary expense incurred. That is not the case, for although all the items are essential from a general viewpoint, a glance at some of the formidable indexes as presented with modern journals convinces the locomotive engineer that it is more than sufficient for his needs and a specially-condensed copy is justified.
Catalogues. The extensive use of proprietary apparatus in locomotive engineering is certainly gaining favour. Consequently the accumulation of catalogues and advertising literature is constantly increasing.
A special feature of the drawing office is the filing and storing of these trade publications. This must be so arranged that any book can be found without delay, and additions made without alteration to the sys
B. Spencer (L.N.E.R., Doncaster, 257) : With reference to the Authors remarks on specialisation, although this assigts where rapid production is desired, it does not tend towards general efficiency in such work as locomotive design. To the active brain, repetition work is monotonous and tends to stabilise design in one direction. New ideas and the mutual interchange of suggestions should always be encouraged. Efficient design cannot be obtained on I mass production lines, and systems which aim in this direction are far from economical in the long run. It is much better to spend extra time at the drawing board and obtain a satisfactory result than to rush a half-considered scheme into the shops to enable a new engine to be sent into traffic at a predetermined date. Work in the shops should not commence until the whole engine design is completed and approved. A point the Author has omitted is testing. This is generally carried out by a senior draughtsman and an assistant junior. It would be more conducive to general efficiency if draughtsmen who have given many hours work and thought to various components of the design were allowed to participate in the trials of the finished engine.
Journal No. 65
Poole, J. (Paper 160)
Argentine broad gauge locomotive design. 299-361. Disc.: 635-56.
Phillipson, E.A. (Paper No. 161)
Notes on locomotive running trials. 363-77. Disc.: 377-86 + 2 folding plates. 2 diagrs., table. 3 facsim.forms.
Tests based at Stratford on S69 (B12) class 4-6-0: but the paper is essentially one on test methodology where a dynamometer car was not available. Footplate observations.
Gresham, J.N. (Paper No. 162)
The comparative utility of ejectors & pumps for working the vacuum automatic brake. 387-90. Disc.: 390-2.
E.M. Gass (391) noted that tests had been made in respect to steam consumption of the small ejector and power necessary to drive the pump. The small ejector consumed 340lb of steam per hour, and the pump took four to five h.p. to drive it. Assuming 30lbs. of steatn per h.p. or 1501bs. per hour, there would appear to be something to be said in favour of the pump, but on the other hand this particular fitting is much higher on maintenance than the ejector. With the pump in service we experienced considerable trouble as regards keeping the rod packing tight. The rod was rigidly connected to the main piston rod crosshead, and any non-alignment disturbed the packing. The design of the stuffing box was of the ordinary fixed gland type, md the packing consisted of four leather rings 5/16in. thick. Probably better results might he obtained with a flexible connection or a packing of the floating type.
Compton, H. (Paper No. 163)
External piping in locomotive design. 393-4. Disc.: 395-7.
Lists advantages of external pipes, including: accessibility.
Haigh, J.H. (Paper No. 164)
Various points in the design of locomotive brakes. 398-9. Disc.: 399-401.
Paper read at Manchester Centre on 18 January 1924.
Three questions are put forward :-
(1) Can the brake power of a locomotive be regarded as sufficient 1
(2) What is the proper position of the blocks, on the centre line, above or below it?
(3) Should driving wheels be braked on both sides, and should bogie and other than driving wheels be braked?
Discussion: E.M. Gass (399) Haigh remarks that in the design of a locomotive, the boiler, cylinder and wheels are the main features considered, and the brake the last to receive consideration. But there is another aspect to this, i.e., the question of curves. The engine having frequently to negotiate curves of sharp radii, the designer is compelled, particularly with engines of the multiple coupled-wheel type, to crowd the driving wheels as close as possible, leaving vtry little room for fixing the brake hangers and blocks, and consequently the blocks are often much below the horizontal centre line of the wheel. The best position for a brake block is just below the horizontal centre line..
As regards brake power, it would appear that engines are very olten insufticiently braked. There are main line engines running with only 45% brake power of the wheels braked, or 25%. of the weight of the engine. It would be interesting to know what should be the maximum block pressure; should this be 60%. of the weight braked, or 60% of the weight of the engine? I am not in favour of brakes on bogie wheels, for the reason that flexible connections are required to the cylinders, resulting in high maintenance, and there is also the danger of the bogie wheels being picked up
The skidding of engine wheels when the brake is applied is probably due to the great variation in the coeflicient of adhesion between the u.hcel and rail. With a very dry rail the adhesion per ton of load is as high as 600 lbs. ; in frosty weather as low as 2001bs.
Journal No. 66
Fawcett, C. (Paper No. 165)
Locomotive valve gears. 402-25. Disc.: 425-9. 26 diagrs.
Presented in Glasgow on 31 January 1924. Mainly the design of the valve gear of the Stephenson link or Walschaerts types in association with piston valves or slide valves (including the balanced type of the latter). Acknowledges the assistance of Collett for providing details of Swindon design criteria for lead., lap and exhaust clearances (see table on valve settings on page 409). Discussion opened by M. Blacklock who stated that aim of development was (a) To save steam and fuel for a given output of work. (b) To increase the output of work for a given weight (c) To get more work per stroke independently of the heat units used.
Spencer, B. (Paper No. 166)
Piston valves. 430-3. Disc.: 433-44.
Paper read before the Institution on 8 February 1924, at Doncaster.
When designed for "inside" admission, the piston valve has a number of important advantages. Short and direct steam ports of large area are obtained, and live steam is not brought into contact with the cool ends of the valve chamber. Also, the valve spindle packing is subjected to exhaust pressure only.
In the Authors opinion an inside admission hollow valve, with single broad rings, offers many advantages. Valves of this type, built up in a similar manner to the Pennsylvania pattern, should be exceedingly light and strong, and could be cheaply produced and maintained. With the object of maintaining a higher steam line in the cylinder up to the point of cut-off, several inside admission piston valves of the broad ring type have been fitted with trick channels on similar lines to the Allen ported slide valve. This feature has not been generally introduced, one reason, no doubt, being that the large valve opening obtained with the simple piston valve renders it unnecessary.
Williams, G.E.H. (Paper No. 167)
Factors concerning the location and lay-out of locomotive shops (contractors). 449-75. Disc: 476-86.
Chaired by G.A. Musgrave, meeting held at Doncaster on 14 March 1924.
The choice of a site for works cannot be too carefully
Site and location of shop in relation to railway traffic and shipping roads.
Labour supply and housing accommodation.
Coal and raw material supplies.
Water supply, power, fuel, drainage.
Local building bye-laws, town planning.
Areas for storage and extension of works.
Cost ot land, restrictions, nature of holding.
Selby, F.W. (Paper No. 168).
Some practical points in locomotive design. 488-514. Disc.: 514-21.
Presented on 22 Februury 1924 at Manchester. With the limited space available on a locomotive every single detail requires the utmost thought and care bestowed upon it in order to obtain the most efficient type for the conditions imposed. The sum total of these various effective component parts will be an efficient whole. Reliability under the strenuous conditions of service should be constantly in the designers mind, together with the thought that a locomotive only earns revenue during the periods that it is hauling a paying load from place to place. To make those periods of useful work form the highest possible proportion of a locomotives life should be the aim of the locomotite engineer. In designing a part which comes under considerable stress it is a good plan to choose the strongest shape, design with a high factor of safety, construct of the best material and then provide an emergency device to come into operation in case ot failure. By thus making assurance doubly sure the cases of engine failure should gradually reduce, and the locomothe department builds up for the railway a reputation for punctuality and reliability of service, which is the finest advertisement possible for the company concerned.
Very much in favour of three, or preferably four cylinders, and of separate sets of valve gear for each cylinder.
Guest, R. (Paper No. 169)
The express locomotive on the northern trunk lines of Great Britain from 1898 to 1923. 523-30. Discussion: 530-5. 2 tables
Presented in Glasgow on 27 March 1924; chaired by W. Chalmers. The greatest changes in the past 25 years are the increase in the size of the boiler, and the introduction of superheating When McIntosh of the Caledonian Railway, in or about 1896, introduced his "Dunalastair" class, the boiler of which had 119 ft2. of heating surface in the firebox, 1285 ft2 in the tubes, (total of 1404 ft2, and grate area of 20.63 ft2, he certainly made a great step in advance of what had, hitherto, been held to be good, and even, perhaps, prudent practice. In the 4-6-2 engines lately put into service on the Great Northern we find that, in comparison with the "Dunalastair", the heating surface of the firebox has been increased by 90 %., of the tubes by 112% and the grate area by 95%, a wonderful advance. The advent of the superheater enabled locomotive designers to lower the boiler working pressure, and to employ larger cylinders. Superheating, had not been altogether an unmixed blessing and many difficulties had arisen in consequence of its introduction, but the Author is convinced that it is undoubtedly one of the greatest advances made in connection with the locomotive since those far distant days when the "Rocket" made its appearance at the Rainhill trials, butand it is a very big butvery little, if any, advantage will follow the application of the superheater, unless the locomotives provided with it are in charge of really intelligent enginemen as opposed to the old-fashioned type of "open and shut" engine driver. The major dimensions of the 4-2-2. 4-4-0, 4-4-2 and 4-6-0 and 4-6-2 operating on the Caledonian, North British, Glasgow & South Western, London & North Western, North Eastern, Great Northern, Midland and Lancashire & Yorkshire Railways are tabulated .
Feed water heating, feed pumps, mechanical lubricators, spark arresters, and many other "gadgets" have had their "exits and their entrances," but, generally speaking, the faithful, long tried, long trusted, and unobtrusive injector stilI sings his merry song under the footplate, and the displacement lubricator, which, by the way, is nothing more or less than an adaptation of the original of the type as invented by Roscoe, as long ago as 1868, still holds the field; spark arresters are, or rather have been, as plentiful as flowers in May, but now, in the main, "have one by one crept silently to rest," as old Omar has it. M. Blacklock was main contributor to discussion.
Kelway-Bamber, H. (Paper No. 170).
Modern steam rail coaches. 537-48. Disc.: 548-54. 4 illus. (photographs)
General comment on the Sentinel type, plus a detailed analysis of operation in Jersey on the Jersey Railways and Tramways.
Discussion: F.J. Bearman (554): With reference to various remarks on lubricators, the Great Western Railway I understand have made tests with various mechanical lubricators, and their adoption of the hydrostatic type is interesting, in face of the adverse criticism which has been levelled against it. Some years ago 1 was engaged on the steam motors of the G.W.R. They seem to be successful as long as the load is kept to one trailer, but as it not unfrequently happens an extra trailer, a horse box and a milk van, are attached, then they become short of steam. If the heating surface could be increased I think it would be an advantage. Some 25 have been broken up, and it seems likely that the remainder will follow suit unless suitable work can be found for them.
Spencer, B. (Paper 171)
Walschaerts valve gear design. 555-72. Disc.: 572-6.
Presented in Leeds on 11 April 1924; chaired by Major Smeddle who on opening the discussuion declared his allegance to inside Stephenson motion. The author's response to the discussion: Mr. Dow raises the question of cost and maintenance. Although the Walschaert gear is much lighter than the Stephenson, it has a greater constructihnal cost on account of the castings necessary to support the radius link and the valve spindle crosshead.
In maintenance, however, Walschaerts has a decided advantage in that, when applied outside, eccentrics and straps are: dispensed with and the radius link motion derived from a simple eccentric crank. By fitting ball bearings to this part of the gear, maintenance cost is still further reduced and permanence of adjustment assurcd. With reference to Mr. Hird's remarks on the location of the reversing shaft, while the lay-out behind the links, shown in Figs. 1 :and 2, was not always practicable, it is possiible to apply this method or radius rod suspension in -. front of the links by placing them within the forks of the reversing shaft so that their centres coincide with the shaft centre. The three-cylinder 2-8-2 type engines recently built for the German State Railways have this arrangement. In order to minimise the distortion of the valve events due to the angularity of the various components of the gear, it is advisable that the radius rod should be parallel to the centre-line of the valve when the gear is in mid-position, and also that the point of connection of the eccentric rod and the link foot should be as near as possible to the centreline of motion of the connecting rod. With very large cylinders a compromise is permissible and the radius link centre may be lowered or the link foot raised to avoid excessive eccentric crank throw, but this arrangement should not be resorted to unless :ibsolutely necessary.
Although small adjustments are often made by means of the union link, it is preferable that any inaccuracies in the valve movements should be corrected by alteration to the link foot offset, if equal port openings at each end of the stroke are desired over the full range of cut-off. The angle of oscillation of the combination lever may slightly exceed the given figure without seriously affecting the operation of the gear.
Maitland. J. Pelham (Paper 172)
Terminal station working. 587-608. 4 illustrations, 2 maps
Presented on 24 April 1924 in London. Auto train working: i,e, push & pull; E.A. Phillipson (p. 596) described terminal arrangements at Liverpool Street; including the provisiopn of water for locomotives. Maps show rearrangement of railways in the Isle of Thanet at Margate and Ramsgate: the latter terminal was extremely difficult to work.
Journal No. 67 (September to December 1924)
Falconer, P.L. (Paper No. 173)
A few notes on locomotive flue tubes and superheater elements. 658-81. Disc.: 681-702. 7 illustrations, 8 diagrams
Presented on 27 June 1924 in Buenos Aires. Effect of water (in Argentina); composition of boiler tubes and superheater elements; arrangement of boiler tubes
Concerning locomotive efficiency. 709-11.
The Locomotive of 14 June 1924 page 197 contains an article entitled "Concerning Locomotive Efficiency"is partly reproduced and formed a dialogue between an engineer and a locomotive engineer. The former made a close study of factors contributing to the efficiency of steam engines, and put this question to the latter:
"Are locomotive designers in general satisfied that nothing remains to be done that could appreciably improve the efficiency of the locomotive?"
The designer defended the locomotive and pointed out that it gave general satisfaction; but went on to note some of the more dificult problems that confront the designer of this type of steam engine: restriction of space, problems of balancing, lubrication, extreme conditions of wear and tear, and with these handicaps, the need to produce an engine yielding good average performance throughout a wide range in drawbar load.
They soon agree that there was no likelihood of considerable improvement being effected in the mechanical efficiency of the reciprocating steam locomotive; and conversation then turned to a discussion of the means by which its thermnodynamic efficiency can be increased and the degree of improvement that might he attained thereby. The locomotive designer considered that systematic and exhaustive research on all combustion, boiler, cylinder and allied questions was thc only policy likely to meet with marked success; and expressed the opinion that this would probably provide data on which the overall efficiency could he nearly doubled.
From this point, the dialogue was reproduced in full to consider obstacles in the way ot the proposed research programme and the financial justification for it.
Engineer: According to the Board of Trade returns for 1921, the fuel consumed by locomotives alone on all railways in England, Wales and Scotland amounted to 10.5 million tons on a total mileage of 465,219,852 (the last year for which complete annual figures were available). The price of locomotive coal in 1921 was much inflated, being on average £2 3s 9d per ton as against 12s 10d in 1913 ,but taking the current rate of £1 per ton it was shown that if overall efficiency doubled, the national saving in fuel would amount to £5.25 million per annum. If, however, efficiency were increased by even so little as 1%, i.e. from 6% to 7%., a saving ot £1.5 million. Would the suggested programme of research cost as much?
Locomotive Engineer: No, nothing like it.
Engineer: So that we have arrived at the conclusion that, on the very lowest estimate, the total cost of this research would be more than repaid by the annual saaing that must follow if all existing locomotives embodied the results of the investigations?
Locomotive Engineer: Yes, but we must remember that the first cost and the maintenance costs of the improved engine might be higher than for existing types.
Engineer: It is purely a question of net costs.
Locomotive Engineer: I am confident that, if the orerall ekliciency of the locomotive were doubled, as 1 think it can be, the resulting economy in running costs would show a suhstantial net gain over any increase in first cost and maintenance charges for the improved engines. Taking an average annual mileage of 80,000 per engine and a coal consumption of 56lb per mile, the year's consumption works out at 2,000 tonS at a total price of £2000. BY doubling the efficiency there would be a gross saving of £1000 per engine, and after deducting increased capital charges and maintenance costs for the improved engines the balance represents a net saving per annum.
Engineer Then expense is not a sound reason for further delaying the commencement of this necessary research.
Locomotive Engineer: I do not think that the railway companies have ever seriously attempted to discover even approximately the ultimate practical limit of economy that is possible in the total annual cost of the locomotive. By total annual costs I mean capital charges, maintenance, and total running costs.