Journal of the Institution of Locomotive
Volume 28 (1938)
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Journal No. 141
Saunders, H.H. (Paper No. 380)
A description of two experimental passenger locomotives built for the Indian State Railways. 2-27. Disc.: 28-39.
Fourth Ordinary General Meeting, Session 1937-38, held Institution of Mechanical Engineers, London, on Wednesday, 15 Decemher, 1937 at 6 p.m.: Lt.-Col. F.R. Collins, President, occupying the chair.
Summary taken from Locomotive Mag., 1938, 44, 21-2. During recent years the Indian Railways had effected considerable improvements in locomotive working and whereas twelve years ago the G.LP. Railway averaged only 52.5 miles a day per engine, the figures had risen in 1935-6 to 72 an improvement of 37 per cent. To still further improve these results by more intensive use of engine power, has given rise to a demand for locomotives that will require the minimum cgtention in sheds and give greater mileage between stoppings ; a regular 10,000 miles per month in pooled service, with a general overhaul in the region of 200,000 miles being aimed at.
To meet these requirements two locomotives were built by the Vulcan Foundry Limited, to the general specification of the Indian Railway Standards Committee and the Great Indian Peninsula Railway, the design being based on the existing 4-6-2 XB type passenger locomotives, first built for India in 1927. Their most interesting features are probably the extensive use of roller bearings, on one engine Timken roller bearing axleboxes being fitted and on the other Skefko roller bearings to the driving crankpin as well as axleboxes. There were therefore considerable differences between the two engines. Apart from this it has generally been arranged that the more experimental features, not hitherto tried out, have been fitted to what might be termed the Timken engine; the Skefko engine being fitted with improvements on existing practice on more conservative lines.
The boilers were identical in both engines and followed normal Indian practice generally, except as regards the fireboxes. These are of all welded steel construction and are fabricated from four plates, the tube plate, the back plate, the throat plate and one plate forming the crown, side plates and combustion chamber; there being one longi- tudinal welded seam at the bottom of this to form the latter. The plates were of special firebox quality acid open hearth steel with a maximum phosphorous and sulphur content of .03 per cent. To increase the strength of the welded joints small half-round bridges ¾ in. by ½ in. by 3½ in. have been used. These were welded on all edges and fixed at right angles to the joint at the water side. Two Nicholson thermic syphons of British manufacture were fi.tted to each firebox, butt welded into the crown and lap welded to flanges pressed in the firebox throat plate. Flue and smoke tubes were beaded over and welded into the tube plate, a copper sleeve being inserted between the tube and plate. Water space and roof stays are of Longstrand steel, except in what may be termed the breaking zones where DL type Flannery flexible stays were fitted.
The ashpans were of the hopper type, which is normal Indian practice, with sloping sides arranged so that all ashes will fall into a central hopper. The hopper is fitted at the bottom with swing doors worked either by hand or steam from the ground enabling the contents to be completely discharged without the delay which has been generally inseparable from the earlier designs. Drenching pipes have been fitted on the right and left hand sides of the ashpan.
As an experimental measure both engines were fitted with Klinger reflex water gauges, with sleeve packed cocks for the steam, water and blow down connections, all in lieu of the standard gauge glasses and columns. In addition to this the Timken engine is also fitted for experimental purposes with Klinger seatless piston type valves for the injectors, ejector, soot blowers, turbo-generator, rocking grate and feed pump, and Klinger sleeve packed cocks for the lubricator, blower and pressure gauge. Klinger valves are of a patent design, and have no seating, the valve consisting of a plunger which moves between two renewable and flexible rings of non-metallic material, leakage being dependent on the fit of the rings on the plunger.
The cylinders were of normal design with Caprotti poppet valve gear, operated by a rotary drive from the main axle through a shaft fitted with Hardy Spicer flexible couplings.
Both engines have linered cylinders. In the Tirnken engine these were of Meehanite iron, grade C heat treated to give a Brinell of 240, and in the Skefko engine are of .5 per cent. low silicon iron. The slide bars of the Timken engine are also of Meehanite iron, but in this case grade A heat treated to give a Brinell of 3\0-330 is used. Although there were considerable differences in the design of the connecting and coupling rods, the rods were interchangeable. This is possible as the crank pins were identical, changing over of the rods, however, is not to be 'recommended as there are small differences in wheel balancing. The rods on the Timken engine were of standard design with bronze floating bushes grease lubricated. As an experimental measure, however, the fixed bushes of the connecting rods have been made of Skefko No. 3 steel heat treated after machining; this steel is similar to that used for ball races.
The rods on the Skefko engine, owing to thc necessity of keeping weight down, are made of 50-55 tons nickel chrome molybdenum steel; they are particularly interesting as the crank pin bearings are fitted with roller bearings. The crank pin is fitted with a self-aligning roller bearing both for the connecting rod and coupling rod; these each consist of a double row of rollers working in a spherical outer race common to both rows.
Grease is used for the lubrication of these bearings, being recommended on account of the protection afforded to the housing seals, and its freedom from leakage as compared with oil. The grease used is a soda soap grease suitable for maximum temperatures of 90 to 100 degrees centigrade, and should not, in normal circumstances, need replenishment between shoppings. Grease nipples are fitted, this has been done as sufficient experience has not been gained to say definitely whether they can be dispensed with or not. It should, however, be explained that the grease nipples fitted to the roller bearings of these engines are different to those used elsewhere on the engines for other qualities of grease. By this method it is hoped to hinder at least, the over industrious Indian Maistris (a not inappropriate name for some at least of the fitters employed in India) who might seek promotion by giving a charge of grease, irrespective of quality, to every grease nipple visible.
Discussion A.C. Carr (28-9) included a table of tractive force per ton of locomotive weight which placed the GWR King class at the top (452), followed by the LNER P2 (406); GWR Castle (396); Lord Nelson (392); Princess Royal (385); LNER Pacific (344); GIPR XP Pacific (315) and BNR GSM (370). Applying the figure of 10.5 Ibs. of steam per hour per sq. ft. of evaporative heating surface, a figure I obtained from the old Indian 4-6-0 engine, .and adopting 5·5 Ibs., the evaporative value of Indian coal, the rate of consumption works out to 7S lbs. per sq. ft. of grate per hour, probably less. Whether economy due to this low rate of consumption compensates for the extra weight involved is, I think, somewhat problematical. 80/85 lbs. per sq. ft. of grate is not uncommon on Indian Railway passenger engines with no difficulty. Perhaps we could not expect the Author of the Paper to refer to the cost of these engines, but as cost of new engines on either capital or renewal account is of impor- tance in railway locomotive budgets, a reference to this matter needs no apology.
The loaded weight of engine and tender is given as 173 tons and I estimate the empty weight to be 128 tons, applying a known figure of cost per ton and allowing for the special fittings and special metals incorporated in the construction of the engine, I hazard the gucss that the cost of the enginc works out to £16,000/£17,000. Translated into cost per 1,000 lbs. of tractive effort which a railway really obtains in the purchase of engines, the extra cost per 1,000 lbs. of tractive effort is approximately 60/70 per cent. .
In spite of my comments, which perhaps you may think somewhat hypercritical, I am sure you will join with me in wishing success to the G.I.P. Rly. locomotive Authorities with these engines and the hope that the expense, skill and thought involved in the design will be justified by the results obtained in service. .
K. Cantlie: I would like to ask what is the increase of weight caused by the adoption of roller bearings? The engine weighs about 10 tons more than the ordinary X B type, but the thermic syphons with the water con- tained in them account for a certain percentage of this, and a number of the other experimental features have also an appreciable weight. .
I have always understood that one of the objections to the use of roller bearings is this increase in weight. So long as they are heavier than plain bearings, their use with limited axle loads will mean a reduction in boiler capacity, and the loss is likely to be greater than the gain. I wonder if it is altogether desirable to instal so many experimental features in one, or rather two, engines? I say this because while I think we can confidently predict tha t these engines will give more satisfaction than the ordinary XB ~ngines-that is, that they will give superior perforrnance-c-it will be a little difficult to distinguish which of the experimental features is the most successful. For example, the thermic syphons will raise the firebox evapora- tion very considerably. The poppet valve gear should reduce steam consumption. Roller bearings will reduce rolling resistance. ;\11 of these will tend to increase the hauling capacitv of the locomotives. But it will not be altogether casv to distinguish how much each contributes to the improved result. .
It is rather fortunate in a way that the designers did not also try a high degree of superheat and mcchanicnl stokers, which would likewise improve the performance, because it would make the problem of assessment almost insoluble, I think. .
There is just one point about the locomotives I would like to draw attention to, and that is the use of a combustion chamber with what appears to be a cylindrical boiler barrel. It seems to me that this causes the front end of the boiler to carrv more water than it need do, which extra weight might be utilized to better advantage in a larger boiler or super-heater. I am not asserting that the extra water is a detraction. but merely that it performs no very useful function. With the wagon-bottom design of boiler, the boiler contracts immediatelv in front of the combustion chamber, thereby lightening the total weight of the boiler. .
There was one other little point I noticed, and that was the use of the two-bar crosshead. I have always believed that the single-bar crosshead is preferable beca use it reduces not only weight, but especially reciprocating weight, which is rather an important consideration, But these crossheads being of a new design, it will be rather interesting to hear the comparison of their weight with that of a good design of single-bar crosshead. Apart from such minor points I think the idea of designing locomotives to run as far as possible between shopping's with as little attention as possible is a very excellent one. I understand the Americans have been paying a great deal of attention to this, but it is not easy to attain. .
J. G. B. Sams: Referring to the mileages quoted in the early part of the Paper, I think wc ought to focus our minds on vcry considerably higher running mileages for engines of such size and'diameter of wheels. Long dis- ranee services should be very easy in this respect, especially in countries like India where the mileages are very long indeed. .
[ hate to quote from a railway I have had to do with, but I remember in Kenya we managed to get 6,500 to 7,000 miles per mensern with engines on a service having an average speed of 20 miles an hour, and I think this should be doubled under more favourable conditions. I should like to add, too, that I regard pooling as a mistake if you want to get a really good result in rnilcagcs and repairs. This statement is rather supported by some of the remarks I have read in the Journal in Papers read by people connected with Indian railways. .
There are one or two points about the ashpan. Ash-pans are subject to very considerable temperatures from semi-incandescent ash. It really seems doubtful whether those ashpans will preserve their shape under considerable temperatures so that you can work all the gear for dumping. It is a good idea, but I have my doubts whether after a bit of use they will be found to be workable. Also the levers for working the dumping of the grate; it does not show from the illustration whether they can be worked from the footplate. If they are, you can shake your ashes down en route, which I assure you is at times very valuable. .
E.S. Cox (31) Although the Paper was very clear and lucid, there are just three points on which I should like a little more information. .
Continuing the last speaker's remarks with regard to the damper gear, the slide which was shown did not show any ashpan doors in the way in which we in England arc accustomed to see ashpan doors. That is to say, there was no door disposed transversely across the ashpan. I rather assumed from the slide that the air inlet for combustion purposes was through a long trough-shaped extension of the ashpan. .
If that is so, I should be interested to know whether this means of admitting air to the under side of the grate distributes air evenly over the whole width, and whether it is as good as the more normal type of ash pan door in this respect. .
In the slide which showed the welded firebox standing by itself, a very prominent feature was the bridge pieces which were shown set across the length of the welded joint, I think between each second pair of stay holes. Could the Author say exactly what is intended to be achieved by these bridge pieces? If the welding is sound in the ordinary straight seam, is that not alone sufficient to give the security and strength required? .
Finally, I was very interested in the idea of using an impregnated asbestos bush for certain spring gear and brake gear parts. I should like the author to say whether these bushes are sufficiently hard and rigid to be incom- pressible; because if they are made of a fibrous material, one rather pictures them as allowing some play of the pin, in which case they might produce a result equivalent to an ordinary steel pin and bush where play has developed. Perhaps he could give some information on this point.
A. F. Webber: When I read that this was dealing with experimental locomotives, I naturally looked in it to see what, if any, features of the experiment were being concerned with what has been my particular interest, i.e., the design and proportions of the boilers. I should like really to follow up in effect Mr. Carr's Comments. Mr. Carr is of the opinion, and he has figures to support it, that, if anything, the tractive effort is rather inadequate in relat_ion to the over-all weight of the engines, whereas looking at the particulars given on page 2S, I thought the boiler looked quite startlingly inadequate for the engine. There are 24 smoke tubes and only 83 small tubes. It does mean that the area through the tubes, which I consider of very vital importance to the steaming quality of the boiler, is not much more than half what is available in some of the latest powerful engines on the British rail- ways which have tractive efforts not so very much in excess of the 30,000 lbs. for the G. I.P. engines. The small tubes, for instance, are not much more than half the number of tubes in the latest L.M.S. Pacifies. I cannot find out from the Paper whether the cylinders and the general proportions of the boilers are similar to the existing engines. If so, presumably they have given good service or they would have been modified. Or are they also of new design, at any rate so far as their proportions are concerned? .
Brown, D.C. (Paper No. 381)
Counterbalancing and its effects on the locomotives and the bridges. 52-111. Disc.: 111-28 + folding plate. 11 diagrs., 12 tables. Bibliog.
Twenty-seventh Annual General Meeting and the Sixth Ordinarq General Meeting of the Session 1937-38 held at the Institution of Mechanical Engineers, London, on Wednesday, 23 February 1938, at 6 p.m.:: Lieut.-Colonel F.R. Collins, President of the Institution, occupying the chair.
Brown was involved in the British Standards Committee on hammer blow. A precis, without the discussion was published in Locomotive Mag., 1938, 44, 86-7.
In the past, when only incomplete data were available, the civil engineer had, in many cases, made impact allowances which are now known to have been excessive. On the other hand, investigations have shown that locomotives have sometimes been balanced with little regard to the bridges and track. In recent years, however, the interest which has been aroused in the effect of impact on bridges has resulted not only in an elimination of extreme cases of bad balancing but in a general alleviation of hammer-blow. Partly as a result of the more complete knowledge of impact effect and partly on account of lower hammer-blow, the civil engineer has in many cases been able to allow an increase in the permissible weight of the locomotive. Thus mutual understanding has been of advantage not only to the two departments concerned, but to the railway organisation as a whole.
It is noticeable, however, that although so much has been done to ascertain the effect of hammer-blow on bridges, there has been very little scientific investigation of the disturbing effects which the unbalanced reciprocating masses exert on the locomotives. Hence, although the locomotive engineer is well aware of the maximum balance which can be allowed, he has little data to guide him at the other end of the scale. Such practical test results as are availab!e seem to indicate that in many cases locomotive designers may have been unduly apprehensive of the disturbing effects of the horizontal forces, especially on the heavy locomotives now used.
It will be seen from the above that balancing is largely a matter of compromise and the purpose of this paper is:
(a) To investigate the methods of balancing locomotives having various cylinder arrangements.
(b) To examine the conditions under which a concession in permissible weight on track and bridges might reasonably be expected in return for a reduction in hammer-blow.
(c) To discuss the limits to which the balancing of the reciprocating parts might be reduced without adversely affecting the behaviour of the locomotive.
The early work of Nollau, Le Chatelier and D.K. Clark, and later investigations by Professor Dalby, the principles of locomotive balancing are well known.
Contributors to the discussion included Gribble (111-14);
K. Cantlie (114-16); emarked that as one who had spent a great many weary hours, and in fact months, in going through bridge forrnulai and the data given in various reports on the subject, he did sincerely congratulate the Author on this Paper. It was an absolute tour de force to have compressed so much learning- into such a small space. At first he began to feel that the Author was rather marching them lip the hill and then down again, like the famous Duke of York, but that is not so, and the Author's final recommendations were concrete.
He said there were one or two things which certainly stood out in the Paper, and also one or two questions which he would like to put to the Author. He thought that all locomotive engineers should study the question of the behaviour of locomotives on bridges and of bridges generally, because not only was it it most inconvenient thing to be in the dark when designing a new engine, and to have to pass it over to someone else to make sure he will accept it, but also it was an intensely interesting subject once one got through the preliminary stages.
He said there was one very obvious thing that the locomotive engineer should press the track engineer to do, and that was to eliminate rail joints on bridges. In these days of rail welding, there was little doubt that welded rails on bridges were practicable, and by welding them it would be possible to allow from 5 to 10 per cent. increase in the static weight, which meant bigger engines on the same track, and that was what most locomotive engineers wanted.
In some of the railways overseas, as in South America, the limit was by weight of the rail, but in China, and he thought in this Country, the limit was the weakness of the bridges. Therefore, in locomotives which were being designed for railways with weak bridges, naturally the specification would be prepared with a bridge loading limit instead of the usual axle loading limit.
The bridge engineer was always under a great temptation to make his bridges too strong. That was natural, because he was held responsible if there was a collapse. Larger and stronger sections did not mean a great increase of expense, and the bridge engineer had the question of age to consider, with premature loss of camber due to excessive loading, for the bridge engineer had to deal with the little habits of his locomotive confreres who were prone to run an occasional main line engine over a branch line bridge through shortage of power. There was every reason, therefore, why he should add just a little extra strength to his bridges. It was for the locomotive engineer to persuade the bridge engineer to reduce his safety factor, and thereby allow the locomotive engineer a little more scope.
He said there was also the question of E.U.D.L. Quite a number of American authorities did not believe in the system of using the equivalent uniform distributed load, though he could nut remember why they objected to it; he thought possibly the Author could say why. On the question of nosing, he agreed that the nosing of engines seemed to have very little to do with the weight of the reciprocating parts.
He thought there was one little point which the Author may have missed, and that was the fact that the limit of the overbalance to 15 per cent. in Germany and to 20 per cent. in other places was to avoid the wheel lifting at high speed through centrifugal force.
In the matter of springs which become locked through friction, he asked if the Author knew whether any improvement or otherwise was found with the use of helical springs? Looked at roughly, it seemed that the helical spring would not suffer from plate friction, and therefore not get virtually locked at certain speeds as did the plate spring.
He thought the experiments carried out on the Madras and Southern Mahratta Railway were noteworthy, for in them all balance to the reciprocating parts was eliminated and yet the engine seemed to run perfectly satisfactorily, except that at certain critical speeds there was a surge, or what the Author called a shuttling effect. In all engines the reciprocating parts were balanced to some extent by the steam pressure in the cylinders. The steam pushes the piston back and the cylinder forward, and vice-versa, and that must to some extent balance the reciprocating parts, though that would not apply with steam off. Unless the experirnents on the Madras and Southern Mahrarta Railway are to be disregarded, it seemed that on certain engines at least the only effect of the complete omission of the weights to counteract the reciprocating masses was to create a shuttling force at certain speeds. This shuttling force must, of course, be eliminated; one could not, for traffic reasons, have a definite surge going on. If sufficient weight was added to effect that, however. was there any useful purpose in adding further weight to balance a certain fixed percentage of the reciprocat illg masses? Most locomotive engineers had a figure which they used, 50 per cent.: 66.6 per cent., 33.3 per cent., and so onl. The mere fact that it was usually a round figure showed that it was more or less chosen according to fancy. The data given with regard to the Madras and Southern Mahratta experiment indicated that extra axlebox wear or general deterioration of the engine did not result from elimination of the counterbalancing of the reciprocating parts, and therefore he would like to ask whether the extra weight was justifiable or whether it was unnecessarily cramping the static weight limit and thereby reducing the possible size of engine on a certain rail or bridge.
A.C. Carr (116-17) said that the Author had pre- sented a masterly Paper on a controversial and difficult subject. Purely from a locomotive point of view, there were certain questions which he wished to ask. Immediately underneath Table VI, the Author summarises the dis- turbing forces acting on the locomotive in five different ways. As regards rolling" on its bearing springs, which was one of the ways which he mentioned. he enquired whether the Author" had considered the relative effect of the rolling of an engine on its ">prings by the use of over- head ami underhung springs, and also whether he had any
E.H. Greet (117-21)
D.R. Carling (121-2) who said there were three points which he would like to mention.
With regard to the shuttling of engines, there was no doubt that at times that could be extraordinarily unpleasant to passengers, quite apart from any effect which it mignt have on the engine itseli in the way of increased maintenance. It had occurred to him that that might be due to synchronism in the natural period of vibration of the buffer and drawhar springs as loaded with the masses of the engine at one end and the train, or part of it, at the other, and the speed rotation of the engine wheels and, though it did not come directly under the subject of counterbalancing, it was a matter which might be looked into on passenger engines. He had been nearly shaken out of his seat in the first coach of a suburban train travelling fast with a tank engine.
He said there was no mention in the Paper of any other means of balancing reciprocating masses than by weights on the wheels. Some recent two-cylinder French engines were fitted with Cossart valve gear, and the driving mechanism was so arranged that the return cranks were at 180° to the main driving cranks, and the designer had deliberately put heavy weights on the end of what we should normally call the eccentric rod at the end remote from the return crank, so that there is a heavy mass reciprocating in exact anti-phase to the corresponding piston and crosshead and nearly in the same line. He asked if the Author considered that that would be a valuable method of achieving balancing of the reciprocating forces without any corresponding hammer-blow The whole gear was described in The Locomotive for April and May, 1933, the latter article containing the part relative to counterbalancing. He also enquired if the Author could give an opinion as to the practicability of balancing a four-cylinder compound locomotive in accordance with marine practice on the Yarrow-Schlick-Tweedie system, bv which all primary forces and couples could be eliminated, but which required uneven crank spacing
who refered to shuttling and mentioned the Cossart valve gear which had been described in Loco. Rly Carr. Rev., 1933, 39, 109
Journal No. 142
McClean, H.G. (Paper No. 382)
The hammer-blow with axle-hung electric traction motors. 140-85. Disc.: 185-97.
Third Ordinary General Meeting of the Session 1937-38 held at the Institution of Mechanical Engineers, London, on Wednesday, 24 November 1937, at 6 p.m., Lieut.-Col. F.R. Collins, President occupying the Chair. Precis of paper from Locomotive Mag., 1937, 43, 382-3.
In the drive arrangement of the so-called "axle-hung" type traction motor, the motor is suspended partly by bearings frigidly fixed on the axle and partly from a nose or projection, on the side of the motor frame remote from the axle, through springs on to the truck or vehicle frame. The motor mass is, therefore, only partially spring-borne, some of the mass being rigidly associated with the wheels and axles. With this type of drive and suspension, therefore, blows occur on the track at irregularites such as rail joints or crossings. It has been assumed that this blow effect severely limits the field of application for this drive and alternative types of more complicated and more expensive and less robust drives have been developed for high-speed electric locomotives. With the increasing adoption of high-speed motor coach trains, where the motors had to be accommodated below the coach floor, and also in the application of electric transmission to Diesel vehicles, where the engine occupied the space above the floor level, it was, in general, impossible to adopt the newer and alternative types of flexible drive and there has been a strong tendency to retain the axle-hung motor.
The author, in his paper, proceeded to review the investigations which have been made of the vertical hammer-blow effects on the track by the axle-hung motor arrangement and to indicate the approximate limits to its successful application. It is clear that the lateral blow with this motor is of equal importance and may be the limit to the application of this type of drive.
In considering the vertical blow effect two problems are involved. The first is the determination of the blow which occurs at a track irregularity, such as a rail joint, due to the passage of a single axle load consisting partly of sprung and partly of unsprung mass. This blow will normally be determinable in terms of the mass, wheel diameter and speed. The second problem is to determine what portion of the total mass may be considered as unsprung-borne in respect of the blows on the track.
Several solutions of both problems have been suggested, but no attempt has been made to consider the complete or dual problem. The author reviewed previous investigations in order to determine, where the axle-hung motor drive is adopted, what portion of the total motor mass should be considered as unspringborne in relation to blows on the track. A main formula is then derived expressing the complete hammer-blows in terms of the total unsprung mass per axle, including the equivalent unsprung mass of the motor, the vehicle speed, and the wheel diameter.
A comparison was made of the hammer-blow effects on a number of high-speed vehicles covering alternative methods of propulsion.
Experience in India. Discussion: W.A. Stanier (186) said it was rather news to him that in electric traction hammer-blow occurs, but thought perhaps he had been thinking rather in terms of a steam locomotive, where they had to Iialance the hammer-blow of reciprocating masses rather than the hammer-blow from which the track might suffer due to unsprung weight. He said the Paper was full of very complex formulae, and when they heard that electric trains of high speed with nose-suspended motors were very damaging to the track, he wondered whether these formulae really served any useful purpose.
He had seen designs of electric locomotives, largely on the Continent, where they went in for all sorts of elaborate arrangements of rods, so that the electric drive could be on a spring-borne portion of the chassis. One of the most interesting that he had seen was the type of electric locomotive used in Sweden, where they seemed to have overcome the difficulty of having a complex triangular connecting rod by putting the drive exactly on the axle centre and having the coupling rod extended through the jack-shaft pin, so that they get a straight drive. He did not know whether anyone could tell them whether the Swedish electric railways ran at high speeds of over 70 m.p.h. If they did, he though it would he very interesting to know whether that type of locomotive was so destructive to the track or so uncomfortable to the passengers as the electric vehicles with the drive that the Author has so clearly set out in his Paper.
C.E. Fairburn (188)said he would like to stress the point raised by Mr. Graham with reference to the title of the Paper. The hammer-blow was not caused by the motor as such; it came from the weight of the motor, and said if a lump of lead were hung on the axle instead of the motor, the effect would be just the same. On the other hand if the track were perfectly smooth there could not be any hammer-blow. He thought it should be made clear that it is not the presence of the motor that causes the hammer-blow.
The opinion, he said, had been expressed that 60 m.p.h. was a sufficiently high maximum speed for a motor coach with nose-suspended motors and he would like to make this parallel. He did not know whether anyone present had been on the Flying Hamburger or the Burlington Zephyr. These were very high speed Diesel electric trains with nose-suspended motors and yet they ran very steadily. He asked if there was so much diff'erence between a multiple unit train arid a Diesel electric train merely because the source of energy .happened in one case to be Diesel engines? His own view was that with proper design there was no reason at all why nose-suspended motors should not be fitted to motor coaches running at speeds very much higher than 60 m.p.h.
He said, with regard to the question of spring drivc, if electrification was to be a success the cost of maintenance had to be low and the fewer parts used, the lower that cost was likely to be. Therefore he did not advocate spring drive unless it was absolutely necessary.
.4 short time ago, he said, he saw some curves giving the results of tests on the shock to the track caused by a side-rod locomotive, a double-bogie locomotive with ordinary nose-suspended motors and a double-bogie locomotive with spring drive. The side-rod locomotive had three driving axles with a load of about 17 tons per axle; the locomotive with nose-suspended motors had an axle load of about r2g tons and the locomotive with spring drive had about the same weight per axle as the side-rod locomotive. The results of the comparison were very interesting because there was very little difference, taking into account the respective axle loads, between the effect on the track of the side-rod locomotive and the locomotive with nose-suspended motors, but the curve for the locomotive with spring drive was extraordinary; it went up, then down, and then up again and it was quite obvious that there were periods of resonance which were not doing the track any good at all. This possibility, he said, could not be overlooked when considering spring drives.
The Author had worked hard in collecting formulae and they are very interesting but he did not think they were really of any practical use.
He believed that on the Southern Railway speeds of something like 80 m.p.h. were attained regularly. On the Liverpool-Southport Railway with stock with heavy nose suspended motors over 30 years old, they got up to 60 or 65 m.p.h. and he thought it would be agreed that on this line, the riding was as comfortable at 60 m.p.h. and over, as it was at 40 m.p.h. He thought that any tendency to reduce speed with nose-suspended motors was going in the wrong direction.
H.H. Swift (189) said they seldom obtained particulars of the effect of axle-hung motors on railway track. Generally speaking the track had been brought into good condition before the high speed Diesel electric vehicles had been put into operation. He did not know that figures had ever been published, for example, on the track between Hamburg and Berlin. He thought that question of track should be borne in mind when deciding which type of drive to adopt..
Nichols, H.J. (Paper No. 383)
The development of passenger rolling stock. 198-212. Disc.: 212-36.
Tenth Annual General Meeting of the Indian and Eastern Centre held at Maidens Hotel, Delhi, on Friday, the 11f February 1938, at 6.30 p.m., the chair being taken by Mr. J. Humphries, Chairman of the Centre. Repeated at. General Meeting of the Southern Branch of the Indian and Eastern Centre held at the Anglo-Indian Institute, Perambur, Madras, at 6.30 p.m. on Saturday, 16 October 1937, when was read by Mr. E. L. Roberts, Chairman of the Branch, on behalf of the Author, owing to his unavoidable absence.
Journal No. 143
Case, C. (Paper No. 384)
Handling and consumption of coal. 249-92. Discusion.: 293-312. illustrations of coal handling plant
Third Quarterly Meeting of the year 1937 of the: South American Centre held at Perez on 15 October: chair taken Mr. F. Campbell, Chairman of the Centre. In Argentina the Central Argentine Railway imported coal mainly from Welsh collieries and was extremely conscious of its expense and problems of damage to it and pilfering
Appleyard, C.E. (Paper No. 385)
Locomotive drawing office practice. 313-51. Disc.: 351-6.
First Ordinary General Meeting of the Centre held on Thursday, 14 October 1937, at 7.15 p.m. in Newcastle-on-Tyne, the chair being taken by Mr. G.W. McArd (Chairman, Session 1937-38). It is not clear whether this was written by a draughtsman at one of the contract builders: Fig. 18 Locomotive data card may indicate that it was so as shoes "L.M.E.R. 2-8-2 pass. tender 8-wheel; gives leading dimensions and publication: Railway Gazette; Railway Engineering, etc. Also rather barbed question from E.D. Trask "that on certain engines, made by contractors, fittings were supplied which were not of a standard nature, more especially with respect to key sizes and threads,, causing considerable difficulty in the running sheds when an overhaul was necessary. The following speaker (E.N. Iley) from the locomotive builde5rs side dismissed this comment. In his formal reply Appleyard stated "that usually the contracting firm had its own standards for unions and so forth, which might not be the same as those standard to the railway company."
Boyle, W. (Paper No. 386)
General considerations of bearing metals. 357-62.
Fourth Ordinary General Meeting of the Scottish Centre held at the Royal Technical College on Thursday, 20 January 1938, at 7.30 p.m., the Chair being taken by Mr. H. Fowler.
Noted that it was almost a century now since Isaac Babbit first invented the lined bearing as is now known in the form of a liner of some strong or rigid material (it is not known whether it was iron or bronze he used) lined with a soft, white metal already stated.
The white metal can be " anchored" in three ways:
(1) By tinning the housing be fore filling with white metal.
(2) By means of holes or grooves.
(3) By a combination of the first two ways.
Theoretically speaking, the first of these ways is ·the best, as, with a careful workman who can take time to do the work properly, a loose bearing is very rarely experienced. To tin properly, many factors come under consideration, the main factors being
(a) The work must be perfectly clean, i.e., free from oil, water, etc. (Oil has a thermal conductivity of 1/200 that of white metal, roughly, and a film of oil between the liner and white metal would form a very substantial barrier to the passage of heat generated in the bearing, making it liable to seizure. Water would cause that bugbear of white metnllers-blow-holes. )
(b) The quality of solder used (just as the strength of a chain is the strength of its weakest link, the strength of the bearing is the strength of its joint).
(c) Care should be taken that the housing or shell to be rnetalled is heated to the correct temperature, for, if too hot, then the tinning would oxidise and cause a bad bearing. (The oxidisation would also occur if the flame of the blow lamp used touched the shell after it had been tinned.)
(2) The holes or grooves method is the one most used in modern "payment by result" firms as it involves less time and is consequently more economical. Generally a heavy V-thread is cut, but a corrugated edge is better, because the top of the V is sharp and helps to crack the metal. The corrugated method leads us to
(3) The combination of the two above methods. This is by far the safest method and enables engineers to use a cheaper solder.
From tinning; we pass to the actual white metalling. You will probably know about the actual process, but the reason for blow-holes is one which interests all of us. Blow-holes can be caused by:
(a) Metal being too hot or not hot enough.
(b) As already stated, shell or mandrel being damp with oil or water
(c) Some of the flux used has been left in the bearing.
(d) Air pockets.
(e) Ladle not held steady.
All of which can be explained.
If the metal has been too hot, when the fitter comes to scrape it, he will find that it is hard and gritty and likely to cause seizure. In this case the only thing to be done is to remelt the white metal and do the job over again. In the case of small internal combution or aeroplane engine connecting rods, some engineers do not fit a brass or bronze bush, but prefer to do their white metalling straight into the ends of the rod. There is nothing against this if due care can be taken in the metalling and a good quality of solder is used, but the metalling of duraJumin rods would require a special technique, special materials and appliances which the average repairing firm does not want to deal with. The reason for this is that trouble is experienced in getting the metal properly tinned, as it oxidises very rapidly and ordinary methods are not much use. There are a great many causes of heating bearings apart from those already mentioned, a few being;-
(1) Unsatisfactory lubrication.
(2) Bad or unsuitable oil.
(3) Shaft beet or too long or too thin causing it to whip.
(4) Bearings too tight.
(5) Bearings out of alignment.
All of which are not within the scope of this Paper.
Testing the White Metal Liner.
There are three ways of doing this, the first is by the ., ringing method." The rod or shell is hit by a small wooden mallet-a metal mallet is misleading. If the ring of the rod or shell is approximately the same as it was before metalling, then it is sound. The higher the note then the sounder, generally speaking, is the bearing. This, naturally, requires the attention of a highly skilled man. The method is fallible, but less so than any other known. The second method consists of taking one bearing at random and chipping out the metal with a hammer and chisel. Anyone can see the drawback here. We have no definite proof that all the bearings are sound because the one picked is sound.
Hewitson, J.W. (Paper No. 387)
A summary of the development of valve gears. 365-70. Discussion.: 370-2.
Fourth Ordinary General Meeting of the Scottish Centre held at the Royal Technical College on Thursday, 20 January 1938, at 7.30 p.m., the Chair being taken by Mr. H. Fowler: paper read by Mr. J. Sinclair, who deputised, in the unavoidable absence of Mr. Hewitson.
Steam was being used expansively in a locomotive cylinder on the Lancashire Witch by Robertson Stephenson in 1828 and it traces back to the Rocket, designed by George Stephenson. Notes the popularity of Walschaerts valve gear and gave poppet valves a cool reception
Discussion:.C.H. Robinson (370) said that he would refer to the subject which formed the last part of the Paper, namely Poppet Valve Gears. Various types were in existence: Caprotri, Lentz and A.L.E. Rotary Cams. Lentz was designed to give motion by oscillating cams driven from Walschaert valve gear. There were also two more types in use on the French rai!ways-Renaud and Cossart. It had, he thonght, been stated by one of the leading French locomotive engineers, that in view of the vastly increased speeds and boiler pressures now ruling, it will be essential to adopt some form of poppet valve gear for main line express locomotives, as the ordinary link motions could not stand up to these conditions. He had failed to ascertain any definite figures as to the savings in fuel, water and maintenance, clue to the fitting of poppet valve g-ears. It would be interesting if Mr. Hewitson could supply these. It was rather extraordinary that poppet valve gear had, so far, made little headway in America-the land of super locomotives. To the best of his knowledge and belief only one set of Caprotti gear had been fitted and about half-a-dozen sets of the R.C. " type.
T.H.B. Miller (371) referred to the remark in the Paper that in recent years Stephensons gear bad been superseded by other types, not because of any defect in the operation of the gear, but because of the unsuitability of its construction for fast and heavy engines. While this was so, be said, would not the Author agree that the valve events, when Stephenson's gear was notched up to short cut-offs, leave much to be desired ? Mention might also have been made. of the Cossart valve gear, wbich was being applied extensively on the Continent. Tbis gear comprised rotary camshafts operating four piston valves, arranged vertically for each cylinder, thereby combining the advantages of the poppet valve witb the rapid port opening of the piston valve. He believed the gear was originally fitted to some 2-8-2 tank engines in France and gave excellent results, it being found possible to work at a cut-off as low as 7 per cent. or even less without trouble frorn excessive compression.
Journal No. 144
Loubser, M.M. and Cox, E.S. (Paper No. 388)
Locomotive boiler design: theory and practice. 377-409. Disc.: 409-41. + 7 folding plates. illus., 11 diagrs., 6 tables.
Note this is very much a paper by Loubser which Cox presented in London in the absence of the Author: Cox did not meet Loubser until 1961 and then in South Africa. Fourth Ordinary General Meeting of the Session 1937-38, was held at the Institution of Mechanical Engineers, London, on Wednesday, 26 January, 1938, at 6 p.m., Lt.-Col. F. R. Collins, President of the Institution, occupying the chair.
This Paper was unusual in that it was the work of two authors who. had not been able ta work in collaboration. The basis was a treatise on the theory of the locomotive which had been prepared by M.M. Loubser, Assistant CME on the South African Railways. This was delivered to the Institution in a condensed form covering the whole locomotive. The second author was requested to deal only with that part covering boiler and smokebox and to expand this into a self-contained Paper. At the same time, it was desired to amplify the original content to cover British practice with some reference to the considerations which influence British boiler design. To achieve this it has been necessary in places to depart from Loubsers text and to add sections not contained in the original communication, while to make the Paper more readable, the actual working out of mathematical formulae is incorporated in the appendices. Due to the short time available and the distance separating thr authors, no form of collaboration has been possible, and the second author hopes that in spite of his editing and amplification he has been able to convey to the Institution the spirit and substance of Mr. Loubsers original communication.
The names best known in connection with this "puzzle of locomotive designers" [blast pipe and chimney dimensions] are Zeuner, Goss and Strahl. Zeuner laid the foundation to the theory regarding the locomotive chimney in his book on the subject published in Zurich in 1863 and in subsequent articles. Goss in his classical experiments with the "Schenectady" put new life into the question and Strahl, guided by the results of both, has, by his experiments of 1905 and 1908, followed up by careful theoretical investigations of the results, thrown fresh light on the question at least as far as non-articulated locomotives are concerned. The theory followed here is that of Zeuner and Strahl.
Page 395: When this cannot be realised constructionally and with the modern big boilers, it is generally difficult or impossible to get the cap low enough with a chimney and a blast pipe cap of ample dimensions to give a free exhaust, a very useful remedy is to use knives or Goodfellow tips, i.e., triangular shaped pieces of metal projecting over the edge of the cap into the blast: Four about *in. to $1. broad projecting iin. to Iiin. tend to spread the blast in a virtual cone of 1 in 4 or 1 in 4.5 so that the divisor of 6 in the above expression can be replaced by 4.5.
Referring to some British examples, Table IV shows that if a divisor of 5 instead of 6 be taken then the results conform, but if the figure 6 of Strahls experiments be adhered to then the blast pipe will require lowering in the engines concerned.
The object of the Paper is to summarise in simple terms the fundamental considerations covering boiler design and to illustrate their application with reference to some modern designs. The boiler is dependent for its draught on the vacuum created and maintained in the smokebox by the exhaust steam, and insignificant as this fact might appear at first sight, yet the whole performance of the boiler is governed by the overall effectiveness of this process. The theory of the boiler, more especially the combustion and transfer
Cox's contribution consists of an analysis of the Stanier taper-boiler with particular emphasis on the four types fitted to the Jubilee class.
Stanier (pp.410-11) adds some notes on the front-end. "I should like to take this opportunity of saying how well I think Mr. Cox has reviewed Mr. Loubsers Paper. I had an opportunity of looking through Mr. Loubsers Paper, and the two sections which Mr. Cox has taken cover very well the essential matter of that Paper, and the linking of it up with English practice is, 1 think, most helpful to members of the Institution. In that connection, there is one thing which has always puzzled me. Reference is made in th.is Paper to the relationship of the diameter of the blast pipe given by the formula on page 396 and the actual diameter of blast pipe used on the engine. There is a striking difference between them, and what has always puzzled me is that a 3-cylinder engine always seems to require a smaller blast-pipe top than one would expect to put on an engine of that power. One of the possible solutinns, of course, is that with a 3-cylinder engine there is not the same volume of steam coming through the blast pipe per pulsation, and it may be that the formula for a 0-cylinder engine should take that into consideration. It is a fact that so far as the locomotives of the L.M.S. Railway are concerned, the 3-cylinder engines generally require a smaller blast pipe than would be expected for their power. The 2-cylinder and the 4-cylinder engines, it will be noticed from Table IV, come very much closer to the diameter given by the formula which Mr. Loubser puts forward.
In discussing the problcm of design of the boiler, it is interesting to find that Mr. Loubser does not dwell entirely on the importance of the smokebox arrangenicnt and the vacuum in the smokebox ; he does link it up with the grate area and the How of gases through the boiler, and indicates quite clearly that the whole of the factors in the design of the boiler have to be in balance if a satisfactorily steaming boiler is to be obtained.
I suppose that one of thc advantages of a steam locomotive over any other power unit is the fact that it can work at such a wide range. The particular engines which Mr. Cox has described, the 3-cylinder 4-6-0 engines, on tests, working trains under the control of a dynamometer, have burned from 301b. per sq. ft of grate per hour up to nearly 100lb. per sq. ft. of grate per hour perfectly satisfactorily. The only factor seems to be the ability of the fireman to put the coal on. The wide range over which steam locomotive5 can be used is one of the advantages of using that type of power. The engine developed something like 1,800 h.p. when burning nearly 100lbs. per sq. ft. grate area per hour, so that it can be seen that the boiler h.p. is even more important than the engine h.p. if the engine is to do the work.
Precis of paper in Locomotive Mag., 1938, 44, 60.
Dumas, L. (Paper No. 389)
The development of rail motor car services in France. 443-58. Disc.: 458-70.
Seventh Ordinary General Meeting of the Session, 1937-38 held at the Institution of Mechanical Engineers, London, on Wednesday, 30 March, 1938, at 6 p.m., Lt.-Col. F.R. Collins, President of the Institution, occupying the chair.
During the past six years, the French Railways had ordered 800 railcars. Of these, 660 had already been put into service, and 140 were still under construction. The 660 railcars in operation covered 90,000 miles every day or 23.5% of the total daily mileage of passenger steam trains in France.
Dicussion: Stanier (458-9) refered to the three four-wheeled railbuses and to the then new three car set that conformed more or less to the power-to-weight ratio of the French steel-tyred railcars. Nevertheless, Stanier ended his contribution with "?He considered there was no difficulty about building light railcars if the service was required, but in England it had to be remembered that the natural fuel, of which there were large supplies, was coal, and the collieries were very large clients of the railways. He suggested that it would he almost a tragedy if they were to introduce the Diesel railcar to any great extent, although he felt that, as had been the experience in France, there must be certain services where it would be worth while introducing a vehicle of that type".
Brian Reed (465) said he wished to draw attention, still further, to the exceedingly workmanlike way in which the French railway engineers had tackled the problem. Mr. Clayton had put his finger on the trouble in this Country, namely, that there was not enough co-operation, and also, as Mr. Stanier had said, we have philandered with the problem. It is very disheartening to many of us that we have philandered with it when every other country in the world, including many with coal resources almost as large as our own, has hundreds of railcars at the present time. He said there was one point with regard to the French services on which he would like the Author to enlarge, and that was the excellent system which they had for maintenance and repairs. He had had the privilege of going through quite a number of their shops, and said they were laid out extremely well. The problem as a whole had been tackled in such a way as to secure the best results. The propeller car to which several speakers had referred., was, he thought, the first practical attempt at the wind brake. It had been suggested in America that a wind brake might be tried by having movable vanes above the top of the car. In the majority of countries the railcar was well below the loading gauge, and the proposal is that certain of the movable vanes might be raised when retardation was required so as to increase the area presented to the air resistance. Possibly the Author would like to enlarge on that point
Keene, D.H. (Paper No. 390)
Machine tool equipment of locomotive wheel shop. 470-92. Disc. 492-501. 7 nillus., 3 diagrs.
Sixth Ordinary General Meeting of the Birmingham Centre held at the Midland Hotel on Wednesday, 16 March 1938, at 7.0 p.m., the chair being taken by Captain G.S. Bellamy.
Wheel lathes, recvonditioning of journals and tyre boring.
Journal No. 145
Wechmann (Paper No. 391)
Electrification of long-distance lines of the German State Rlys. 508-20. Disc.: 508-35. 7 diagrs.
Eighth Ordinary General Meeting of the Session 1937-38 held at the Institution of Mechanical Engineers, London, on Wednesday, 27 April, 1938, at 6 p.m., Lt.-Col. F.R. Collins, President of the Institution, occupying the chair.
W.A. Stanier (522) said he found one paragraph in it which was very comforting, namely, where the Author said " With all the advantages of electric traction, it cannot be said that the steam locomotive, in some form, will ever be replaced, at least in countries having rich coalfields." On the other hand, he thought the fact that as the Institution was an Institution of Locomotive Engineers and not of steam locomotive engineers was all to the good, because one could not help feeling that the developments which were taking place and the fact that electrical engineers were at last getting down to a common multiple, so to speak, for the way in which the power could be used, meant that that Institution had to consider electric traction as well as steam traction. The Paper which they had just heard, showing what had been done in Germany in that regard, was a very interesting and a very useful contribution to the Proceedings of the Institution.
Pargiter, G.M. (Paper No. 392)
Economics of locomotive running-shed organisation and administration. 535-62. Disc.: 563-8.
Fifth Ordinary General Meeting of the Newcastle Centre was held at the Royal Station Hotel, on Tuesday, 8 February 1938, at 7.0 p.ni., the chair being taken by Mr. McArd.
Sequel Paper No. 397.
Summer Meeting in Scotland, 8th to 12th June, 1938.
It is significant that the party included 17 German engineers including Dr. Dorpmuller (Minister of Communications), Herr Bergmann, and Dr. Wagner. A far shorter description appeared in the Locomotive Mag., 1938, 44, 206-8 which fails to mention that Dr. Dorpmuller travelled to Scotland on the Coronation with Sir Nigel Gresley
Run to Glasgow, June 8th. 574-81. + folding plate. diagram, table.
Behind No. 6225 Duchess of Gloucester: includes illus. and side elevation of locomotive and reproduction of dynamometer record
Sunday 12 June, 1938. Contribzrtcd by K.R.M. Cameron. 593
For the final day of the Summer Meeting, the London and North Eastern Railway Company had very kindly invited all the members to be their guests for the day. The weather was bright and cheerful, and in the morning the whole party assembled at Queen Street Station, where a special train of modern articulated vestibuled stock was arranged to take the members to the Forth Bridge.
Prior to departure many of the party proceeded to the end of the platform to inspect the streamlined 4-6-2 engine Empire of India, which \vas to haul the special train (see Fig. 4). Herr Kuhne was very interested in the Buckeye coupler fitted to the coaching stock, and the writer managed to give a very short description of the fitting to him until it came to describing the corridor connections, at which point the language difficulty proved too great at task, but the situation was saved by the timely arrival of Mr. C. H. D. Read, whose knowledge of German enabled the description to be completed to both party's satisfaction.
The journey to Dalmeny proved all too short, but even for the short time the London and North Eastern Railway Company demonstrated their thoughtfulness by serving coffee and other light refreshments throughout the train. At Dalimeny half of the members detrained to walk northwards over the Forth Bridge. The train then proceeded to North Queensferry to detrain the remaining members who were to walk southward, but due to some slight misunderstanding the train sped through the station and tunnel, and was stopped in the cutting by Mr. Musgrave's prompt brake application via the communication cord. Scottish comment of the dreadful risk he had run was general, but so far all that is now known is that Mr. Musgravc has been promoted to be Locomotive Running Supt. Western Section), Southern Area. Having no less a person on board than Mr.. Gardiner, the L.N.E. Scottish Superintendent, we were treated to a spectacular piece of propelling work up hill, and in no time we were back in North Queensferry Station .
Although forty-eight years old the Forth Bridge (see Fig. 12) still remains one of the wonders of the world. It is to be wondered at that such a vast project could be carried out 50 many years ago and still be regarded as a marvel of modern engineering in days when technical progress is so rapid that what was a marvel one or two years ago is now almost commonplace, or even out of date. The details of the bridge were very fully explained and pointed out by Mr. Fraser and his assistants, and quite a number of members placed coins on the rails to have them flattened by the wheels of passing trains. One member placed a penny and a threepenny. bit on the rail, but when the train had vanished all that was left was the penny. Apparently the train was an express to Aberdeen! A number were lucky to find numerous coppers on the bridge, this being due to the superstition among passengers that on ones first journey across the bridge a coin should be thrown into the water. Many of these coins, however, strike the steelwork and are deflected back on to the floor of the bridge. A few inembers descended into the worlanens hut situated below the rails at the centre of the bridge, and the general opinion was that they all felt safer on dry land than climbing about steelrvork up to 300 or so feet above water level.
At least three members of the party reported that they crossed the bridge on foot before it was completed. The members then entrained at the centre of the bridge, the train being stoppccl specially at that point to pick up the party. During the short run to Edinburgh our hosts again thoughtfully proyided each with a glass of excellent sherry.
On arrival at the North British Station Hotel the party was entertained to a most delightful lunch, still as the guests of the railway company, after which a speech of welcome from Mr. George Mills, Divisional General Manager of thc. London and North Eastern Railway, was suitably replied to by Mr. Stanier, the President of the Institution. In thc afternoon five motor coaches were placed at our disposal, together with experienced guides, and two very pleasant: hours were spent visiting the Palace of Holyroodhouse, the Royal Mile, the Castle and Scottish War Memorial Chapel.
On return to the North British Notel afternoon tea was served, and shortly afterw tlie majority made their way back to Glagow in the special train, some of the members returning to the south direct from Edinburgh. So ended the 1938 Summer hleeting of the Institution of Locomotive Engineers. The visit was blessed with good but not brilliant weather, but with such a full programme few noticed what the weather was like. All the German guests enjoyed themselves thoroughly, and all wrre loud in their praises for a most successful meeting.
Meeting at Midland Junction, Western Australia, 27th May, 1938. 596-605.
Meeting of the members on the Western Australian Government Railways at Midland Junction held on Friday 27 May 1938. The chair being taken by Mr. F. Mills. The Chairman announced that no Paper was being read, but introduced Mr. W. Raynes who opened a discussion on Locomotive Crossheads.
Mr. W. Raynes : Crossheads, in his experience, were probably more troublesome than any other important detail of the engine. In some cases breakage of piston rods at the crosshead cotterway had been cured by shrinking a band on the barrel of the crosshead. Cast steel crossheads on our largest 4-6-2 engincs had broken in several ways, some having cracked through the gudgeon pin holes while others had failed at the junction of barrel and sides. Various other troubles had been experienced and the following notes had been compiled in an effort to place before members various features of crossheads now in use on this railway system.
Journal No. 146
Cook, Maurice (Paper No. 393)
Copper and copper alloys for locomotive firebox construction. 609-42. Disc.: 642-7. 25 diagrams., 7 tables
Fifth Ordinary General Meeting of the Birmingham Centre held at the Queens Hotel, Birmingham, on Wednesday, 16 February 1938, at 7.0 p.m., the chair being taken by G.T. Owen
Metallurgical paper which pointed towards higher quality copper with lower oxygen and arsenic contents. F.J. Pepper (642-3) asked if Kuprodur could be used in welded copper fireboxes and noted how Germany had advanced the welding of copper fireboxes.
Baldwin, T. (Paper No. 394)
The fatigue strength of machined tyre steels (including some general notes on fatigue and related matters). 649-84. Disc.: 684-722.
Second Ordinary General Meeting of the Session 1938-39 was held at the Institution of Mechanical Engineers, London, on Wednesday, 26 October, 1938, at 6 p.m.: Lt.-Col. F. R. Collins, Past President, occupying the chair. An abstract appears in Locomotive Mag., 1938, 44, 362-3.
A high proportion of the breakages of locomotive parts in service are due to fatigue. On examination such fractures are seen to have occurred at "fatigue flaws which slowly grow into the sound metal until the latter suddenly breaks in a very brittle manner. These service fractures, with a complete absence of plastic distortion, are very different from the fractures obtained in a tensile testing machine. The latter type shows no signs of a smooth growing flaw and the test piece is seen to have altered its shape considerably during the test. The fracture of tyres in service is a matter which is naturally regarded seriously by locomotive engineers: cited work by C.W. Ridges (Paper No. 261 in 1930) and E.S. Cox (Paper No. 346 in 1935). The author worked for the LMS at Derby
Discussion:. T. Henry Turner, (685), saicl the Institution was undoubtedly indebted to the London, Midlanrl and Scottish Railway Company for allowing- the information contained in the Paper to be put before them, because it was very valuable. The Author had no need to apologise on the ground that it was not complete, because he had covered verv manv really important points. ' .
The Author, he said, had emphasised the fact that it was possible to have a surface with a stress concentrating' power: and that that differed according to what was done to the surface, The nature of the borings or turnings would help to show that. He claimed if the turning came off like a coil spring there would be residual cracks left in the bore at right angles to the direction of tool movement. On the other hand, if the tool produced a spiral turning then the cutting' would be on the side of the tool and the next cut would remove the part of the tyre bore which had the cracks in it, and the face of the tool would he regarded more as a burnishing tool. He knew from the studv of microstructures that that was the case. The Author had not shown any microstructures in the printed copy of the paper, but that fact could he shown very clearly; there was no doubt, he said, that if the cut was made on the side of the tool it removed the cracks which were made by the first cut. .
The second point which it seemed to him that the author had emphasised was that the fatigue limit of the steel had to be considered in thv place when; the stresses had been concentrated. As a matter of fact, when he got some of the specimens to break on the back that was showing, as he pointed out in his introduction, that that was a little way in frorn the surface, Owing to the slow penetration of the cooling water effect during the finishing operation, or during whatever other heat treatment that the tyre had, the hardness there was less, and, the fatiguc strength in any given ordinary atmospheric condition being proportionate to the ultimate tensile strength or the Brinell hardness, that should give a lower fatigue strength behind,
It wa s true of all old tyres that they had cracks in them, He had photographic evidence that the cracks are in both directions on the tread, in almost every tyre that had ever been in service and they were of little or no irnportance there in locomotive tyres because that part was in compression, but they were of very great importance on the part with which the Author had dealt (the inside of the bore), In a low lzod strength steel (as all these hard steels were) cracks could not be allowed on the inside of the bore, where they would tend to open. What he said, the engineer had to do was to prevent the stress first of all, if that was possible, and secondly, the crack, The stress could be prevented by making a stronger wheel rim, There was no doubt that many of tlw driving-wheels of the older locomotives had very poor bridges between their spokes, Very often in such cases it would be found that the piece between the spokes was flat, but its function was to bridg« between the two adjacent spokes and in some modern designs the engineer had taken that into consideration and made a much better bridge between the two spokes, The whole weight of the locomotive was trying' to break the rim there as though holding it in a fork, and that was why those stresses could be avoided by the use of disc wheels. They were not used in [Britain], but the Arnericans used them. Some of the more recent British loco. driving wheel designs also minimised the bending stresses on the tyre.
There was not just one fatigue strength for a tyre; there were many depending upon the location depending in the cross section where one cuts the test specimen, Any piece of steel, whatever its hardness, had a different fatigue strength in different directions, He had brought with him some photomierographs mounted on blocks to show cross, transverse and longitudinal sections of two tyres and two rails, In one of the cases there were three fatigue cracks in three different planes, They showed that the fatigue strength of a piece of steel would vary very much in the ctirection in which it was stressed, because of its microstructure. The odd thing was that lumps of slag, and even actual holes, very seldom broke tyres. In one case. a tyre finlshed a long service life with a definite large cavity at the root of the flange. The cavity was only seen after the tyre had been returned several times. .
The internal stresses were not referred to m the Paper, but when he had to examine some tyres six or seven years ago for a similar type of failure he found that the stresses were very much accentuated by the internal stresses left In the tyre owing to the method of heat treatment, and that was a feature which had to be noted. Surface tear during machining also left internal stresses and stress concentration at fissures which facilitated fatigue failures.
The Author mentioned one other feature, corrosion, which was most important in railway work, because of the sulphuric acid in all the tunnels, and how bad that was would be appreciated by the fact that an 85lb. rail section was reduced to 75lb. in a tunnel and to 62lb. under a ventilating shaft. That ruled out all question of composition, because it was the same rail; it was simply the effect of corrosion. Corrosion fatiguethat was, fatigue where the crack was opened out not only by the stress, but by chemical actionwas something which had to be encountered, and any tests given in the Paper which were done in the laboratory merely gave an indication of what happened in service to a much worse extent. He asked the Author whether he had considered the possibility of reduclng the tenslon stress on the inside in much the same way as that in which a compression stress was left in a piston ring. In the old method of making a piston ring , the outside was hammered. If the finished tyre were shot-blast on its inside bore, or hammered a little, uniformly all round by mechanical means, it would not only fill up such fissures as .were left by machining, but would leave a little compression stress, which would neutralise some of the tension which would be applied in service. Had the Author cons'ldered that, and did he regard it as impractical.
Hart, W. (Paper No. 395)
Welding and cutting in a railway workshop for repairs and fabricated structures. 722-43. Disc.: 744-50. 19 illus. (including microscopic images), diagr.
First Ordinary General Meeting of Manchester Centre held at the Manchester Literary & Philosophical Society on Wednesday, 26 October 1938, at 7.0 p.m.: the chair being taken by F.W. Abraham.
Five sections with the following headings
Methods of repair in a locomotive repair shop.
Cast iron welding
Design for fabrication by welding.
Cutting for fabrication.
Concludes with LMS welded tender.
Informal Meeting, 13th October, 1938. 752.
Informal Meeting held on Thursday, 13 October 1938, at the Institution of Mechanical Engineers, London at 6 p.ni., Mr. J.N. Maskelyne, read a Paper on The Design and Construction of Modern Miniature Steam Locomotives for Passenger-carrying purposes.
There was a very good attendance of members, who heard with considerable interest of the difficulties encountered and the ingenious methods adopted by the designers and builders to overcome them.
The Paper is not being published, but a copy is filed for reference. This can be inspected during the usual office hours at 28, Victoria Street, London, S.W.I