Journal of the Institution of Locomotive
Volume 18 (1928)
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Journal No. 83
New L.M. & S.R. locomotives. 2-6 + 5 folding plates. 2 illus.,
2 diagrs. (s. els.), 4 tables.
The results of dynamometer car tests on the new Royal Scot class were compared with tests on the 4P compound and "Claughton" (both original and modified) classes. Also new 2-6-4T.
Moon, A.N. (Paper No. 221)
Designing of carriages for comfort. 7-27. Disc.: 27-31.
The Meeting held in Glasgow on 16 December 1926 was chaired by D.C. Urie.
Mainly concerned with a mathematical analysis of the factors which affect vibration in carriages, especially the relationship between the bogie and the track including the shape of the wheel tread and its eccentricity and the suspension springs. Both the paper and the discussion give some consideration to the six-wheel bogie.
Heaton, W. (Paper 222)
Carriage bogie design (Part II). Riding qualities and the effects of design on wearing parts. 38-64. Disc.: 64-128. 1929, 19, 334-6.
Preseented at Perez, Argentina, on 30 September 1927; chairman E.C. Noble. Part 1 published in Volume 13 Paper 149. Considers laminated bearing springs, carriage bolster springs, carriage side bearing springs, coil springs and laminated springs, and helical springs over axleboxes.
Stephenson, H.J. (Paper No. 223).
Locomotive engine failures and their causessome hints for their prevention. 133-44. Disc.: 145-58.
Based on failures in the North Eastern Area of the LNER. The largest single category was overheated bearings (category included axleboxes, big end brasses and crank pins): 30% attributable to this cause. He placed most of the blame on failures in lubrication, and considered that force feed lubrication was the cause. He also considered that the quality of the metal used for bearings had declined. 13% of failures could be traced to burst or leaking tubes and the primary cause was untreated very hard water, although excessive use of the blower (termed jet) was a further cause. Injector failures accounted for 7-8% of failures and these could be traced to dirt (some via water troughs) and to badly fitting replacement cones. The motion and glands accounted for 19% of failures, and those attribuable to connecting rods and big ends were increasing. Joints accounted for 3% of failures. Superheaters increased the problem, especially from the main steam pipe in the smokebox. Springs and spring gear accounted for 3%. The spring hanger over the radial axle on the 4-4-2s was an especial cause of trouble. Axle failures were very rare: about 1%. Crank axle life could vary from 50,000 to 800,000 miles. The bending and breaking of side rods was a problem on the 0-8-0s. Coupling rod pins were a considerable source of trouble. Crank pins occasionally broke. 3% of failure could be attributed to pistons and piston valves. He prefered the Detroit lubrication system. The Gresley Pacifics experienced problems with union links and combination levers and the loss of Castle nuts. The predominantly Westinghouse brake gear accounted for 4% of failures, especially breakage of the reversing valve. Discusssion: G.A. Musgrave (145-8) chaired the meeting and was critical of both the overheated bearings and of Stephenson's criticisim of mechanical lubricators. He strongly advocated hot water washing out. E. Alcock (148-9); C.F. Adams (149-50); Burley (150)..
Adams, C.F. (Paper No. 224)
Piston gland packing. 159-70. Disc.: 170-5.
The Chaiman (G.A. Musgrave) observed when opening the discussion that the main object of piston gland packing is to prevent the escape of steam from the cylinders, and engines using highly superheated steam adopt cast iron packing, especially for passenger and express work. The Britimp packing was giving exceedingly good results on the engine upon which it had been fitted (a Gresley Pacific). When this packing was fitted, the rings were taken from the boring machine and put on the rods without any scraping whatever, and when the engine was steamed and moved there was no blow at the glands.
The United Kingdom packing gave very good results for superheater engines. A good feature of this packing and gland was air cooling: the housing for the white metal rings was exposed to the atmosphere and tended to reduce the temperature of the rings. The two garter rings were also a distinct advantage, and tended to keep the high temperature steam from the packing, but the joints between each segment of these rings needed to be lapped.
Cast iron packing gave good results on the majority of British railways: it was simple and adaptable. Good class metal was needed, and special care was needed in setting and hardening the elliptical or clip spring, to avoid excessive pressure being put on the rings, which, in turn, would cause piston rod wear.
Wear on piston rods due to packing:
|per 100,000 miles
|Ring life (miles)
|Cast iron Britimp
|Bell's bronze & Castle
Adams, C.F. (Paper No. 225)
Connecting and coupling rod lubrication. 175-85. Disc.: 186-93; 344-51..
Journal No. 84
Carrick, Peter (Paper No. 226)
Train lightinng. 201-16. Disc.:217-22 + folding plate. 6 diagrs.
Presented at the Royal Technical College in Glasgow on 24 November 1927. Chaired by C.H. Robinson. The voltage generally adopted in Great Britain for train lighting was 24. This comparatively voltage had several advantages: robust filaments in the lamp circuit more able to withstand the vibration from within a moving vehicle; elimination of risk of fire from an electric arc; less risk of electrical leakage and consequent loss of energy from the accumulators. The widely used Stone's System included the then more recent Lilliput dynamo; variable speed equipment, the Vicker's single battery system and the Vickers V1 system. Accumulators. Considered Faure, Plante and Tonum cells.
In this Paper on train lighting the Author has attempted to give in as lucid a manner as possible an explanation of the working of a train lighting equipment. In the short time at his disposal numerous points had necessarily to be very briefly touched upon and many interesting details of those little "automatic power stations on wheels were not mentioned at all. Discussion: I. Kempt (217) commented on slipping belts; W. Henderson (217) commented on the power absorbed. K.R.M. Cameron (communication: 219-20) commented on nickel iron cells, mounting the dynamo on the bogie and electric carriage heating.
Tomlinson, Frederick (Paper No. 227)
The use and collapsing strength of copper flue tubes for locomotive boilers. 223-31. Disc.: 231-6 + folding plate. 4 diagrs.
Presented at LNER Mechanics' Institute, Doncaster on 25 November 1927. Chairman: G.A. Musgrave. Author was Director of Broughton Copper Co. Ltd., Manchester. G.A. Musgrave (231-2) commented on the relative costs of steel and copper, but also noted their scrap value; Refering to the test which Author had made, he thought in that particular case pressure was applied to the outside of the tube, but the question we must take into consideration with the locomotive boiler in actual practice is the temperature of the hot gases passing through the tubes, which ranges from 1000°F. at the firebox end to 600°F. at the smokebox. In addition, there is the external steam pressure of, say, 220 lbs. per sq. inch, corresponding to a temperature of 389°F. In his opinion, these are very different to the conditions under which the test was made. E. Windle (233) preferred copper, but cost had to be considered; regarding tests, while these are undoubtedly interesting and convey much useful information, the conditions under which they have been taken are not exactly those which obtain in the locomotive boiler, for in addition to the temperature and pressure, the tubes in actual practice are subject to bending stress, vibration and stress due to constant expansion and contraction of both tubes and boiler. The Author has used a temperature of 540°F., and the tests have shown that this temperature has little or no effect on the tensile of the material. Could he say at what temperature he would expect any considerable reduction in the tensile stress? Would it be possible to return to the copper main steam pipe with a maximum temperature of approximately 750°? E.A. Cleaver (233-4) commented on the temperature of the flue gases; R.L. Vereker (234) questionned whether the thickness of the tubes was uniform; T. A. Street (235) asked if the Author could give any experience of tests caried out under conditions more approaching those under which the tubes are used. That is the tubes fastened in tubeplates 20 feet apart and subject to the excessive vibration which is set up by a locomotive travelling on the rails. He had in mind the possibility that some of the tube failures, that is the collapsing of the tube, may be due to fatigue of material, of which this vibration may be a contributory cause. The condition may be difficult to introduce into a test, yet it is not impossible and might probably add further to our knowledge of stresses on tubes under working conditions. C.F. Adams noted that leakage through copper tubes was a lesser problem than through steel; F.H. Eggleshaw (235-6) commented on cost of copper..
Bulleid, O.V.S. (Paper No.228)
The booster. 239-74. Disc.: 274-91+ 13 folding plates. 5 illus., 29 diagrs. (incl. some folding), 8 tables. 2 plans.
This was a highly detailed paper and is illustrated with a very large number of diagrams. Bulleid attempted to justify the advantages of the wide firebox, but his arguments were destroyed by Clayton, and Chambers detected considerable weaknesses in his argument. Very interestingly, Chambers cites the Diamond paper on the 3-cylinder compounds in his defence of Derby locomotive design. The history: Verpilleux fitted cylinders on a tender om the Lyons-St. Etienne Railway in 1843. The Sturrock steam tenders are also mentioned and The Engineer, 1919, 17 January is cited. Bulleid attempted to show the advantages of the wide firebox in terms of steam generation using a formula adopted by the American Locomotive Co. which compared 4-4-2, 4-6-0 and 4-6-2 types and suggested that the coal required per ft2 of grate area would be 128 for the 4-4-2; no less tha 228 for the 4-6-0 and 153 per hour: this led to fierce responses from Chambers and Clayton. C1 Atlantic was fitted with a Franklin Supply Co. booster in 1923 and was tested on a run from King's Cross hauling 18 coaches weighing 535 tons on 29 July 1923. The aim was to establish whether the locomotive could start and re-start with such a load. On 28 August 1923 the booster-fitted locomotive worked the 11.30 King's Cross to Grantham. The two P1 class 2-8-2s were fitted with modified boosters in which the thrust was transmitted to the main frame through pivoted thrust blocks, rather than through the axleboxes and guides. It was claimed that the boosters increased haulage capacity by 19%. Tests with the Atlantic had shown that it was difficult to engage the booster at slow speeds. This modified booster was tested on the 1 in 96 of Cockburnspath bank where it was foound that the booster enabled trains to restart at a signal where the unfitted locomotive would stall. Further modifications were made to the booster to improve ride. Noted that booster valve gear was contained within an oil-bath.
Discussion: Lawford Fry (274-5) suggested that Bulleid's equivalences of draw-bar horsepower as being 90% of cylinder horsepower were rather low. He also noted the use of four-wheel trailing reucks in the USA and the use of tender boosters where training axles were not fitted. E.C. Poultney (275-9) illustrated a New York Central Railroad booster-fiited 4-6-4 with an 81ft2 grate area. R.W. Reid (279-80) noted that there was a renewal of interest in steam tenders in Germany. He was also highly critical of Bulleid's theoretical justification of wide fireboxes, and asked if booster-fitted Atlantics should be constructed in preference to Pacifics.
H. Chambers (280-1) acted as Sir Henry Fowler's messenger to criticise Bulleid's comments on the boilers mentioned. He also noted a further early booster-fitted locomotive constructed by Beyer, Peacock in 1865: a 2-4-0 for the Tudela and Bilbao Railway, Spain which was arranged to drive on the leading pair of wheels. Whitelegg (with illustration) The Engineer 1923, 11 May. Regarding the boiler particulars quoted for the Pacific, Atlantic and Royal Scot types, the American formula adopted presumed 55 lbsft2. of steam per ft2 of firebox heating surface and about 10 lbs. for the tubes, but when comparing actual boiler performances they require to be treated very carefully. For example, the Claughton boiler is not considered to be a very good steamer, yet on the basis of Bulleids figures the Claughton boiler would give a steam evaporation of 24,700 lbs. of steam as against a figure for the Royal Scot of 25,272 lbs making the Claughton boiler nearly equal to the Royal Scot boiler, but this was not suppoprted by actual performance. In using these theoretical figures very great care should be taken with regard to the disposition of the boiler tubes and the length of tube compared with the diameter and other ratios, citing Lawford Frys very exhaustive conclusions on boiler ratios and design. In the case of a wide grate it might be assumed that the back corners of the grate are likely to give trouble and therefore will not give as efficient combustion as the front portion of the grate. Lawford Fry and Poultney referred to the proportion of the drawbar horse-power-hour being taken as equivalent to 90% of cylinder horse-power-hour. Often the locomotive weight might be 25 to 30% of the gross weight of the train hauled, thus "we are entitled to take a very much more liberal figure than that quoted." Referring to figures quoted in the Paper, Collett had pubished figures of 2.1 lbs of coal per ihp/hour and 2.83 lbs. per dbhp/hour: a ratio of 1 to 1.36. Diamond, in a paper read before the Institution of Mechanical Engineers on the LMSR Midland Division 3-cylinder compound engine, went into the question of dbhp/hour coal consumption as against ihp hour coal consumption and gave a figure of 1.38, and therefore suggested that Bulleid should modify the ratio of dbhp/hour to ihp/hour proposed.
J. Clayton (281-3) argued strongly against Bulleid's assertion that nothing but a boiler having a wide firebox is economic, and that such ordinary engines as the Lord Nelson, the Royal Scot and the King George V "are not in it". As Chambers had pointed out, if these figures show a correct deduction there would be no need to build Royal Scots. He requested Bulleid to show how the figures given in the Paper were arrived at. Bulleid (page 291) responded Mr. Clayton is a more persuasive advocate of the narrow box than I of the wide. Mr. Ivatts small and large Atlantics are convincing examples of the advantage of increased boiler capacity. The designer should constantly keep before himself the future and the probability that it will demand greater loads and higher speeds, and that the success of his design will depend upon the engine being able to cope with such increased demands during its useful life. The wide firebox gives him greater latitude in designing the boiler.
Clayton continued: it is an historic fact that the Castle class engine of the GWR did as good work as the LNER engine when the two were exchanged, and yet the LNER engine was 12 tons heavier than the Castle engine, so that either the LNER engine has a boiler which is too large or the Author is making out a very good case for the use of a trailing axle, which cannot be required for any other purpose than that of carrying the wide firebox. "I am not prepared, therefore, to subscribe to the conclusion reached by the Author as to the superior capacity of the wide firebox engine, and would point out that the Atlantic engine could have a firebox having 30 or 31 ft2 of grate with a narrow firebox between the frames and the figures would have been the same.
"Would the Author tell us the cost of fitting a booster and also something about its maintenance in the sheds, and whether Mr. Gresley after his experience is likely to increase the use of the booster? For myself, I would suggest it might be more economical to increase the boiler pressure or the cylinders or both, and provided you fit a good valve gear which can be notched up close you have the opportunity to draw on the extended cut-off when you are lifting the train or facing a heavy gradient, and can notch up close to run at speed, when the tractive effort required is small. It would seem to be a question, therefore, whether the additional axles required to carry the wide firebox are altogether necessary, or is the suggestion to use the booster with such engines an apology for making use of a wide firebox, which requires a trailing axle. If the booster could be fitted, as the Author points out, to the front engine bogie, just as in America they have applied it to 4-wheel bogies under the wide firebox, the exhaust pipe would be very short, and that would no doubt conduce to the efficiency of the booster."
W. Cyril Williams (283) looked at the booster from the point of view of its application not only in this Country, but through-out the world. It therefore resolves itself into a question of costto which aspect Reid and Clayton had already referreddoes it pay to put a booster on an engine? A good many engines I have come across in many parts of the world are under-boilered and would not stand a booster, particularly on a grade where difficulties are being experienced owing to shortage of steam. But taking a boiler which has something to spare we come to the cost of the booster. Let us take the case of the L. & N.E.R."Pacific " engine, and assume, for the sake of argument, that it costs £12,000, and that a booster costs at any rate £2,000. Now for £12,000 you could get an articulated engine, developing 50 per cent. more tractive effort and having a boiler which, owing to the principle of articulation, can be developed to meet the maximum cylinder demands, such locomotive stressing the track less into the bargin. It seems to me, therefore, that before applying the booster to a new engine the whole question should receive very careful consideration.
W.A. Letean (283): understood a booster to be an additional power unit which is only intended to be brought into service for short periods when help is necessary to enable the main engine to deal with a temporary overload, and not as an extra constant drive engine. If an extra engine becomes necessary it is then a question whether, as Mr. Williams suggested, it is not better to go in for an articulated engine rather than put an engine on the tender. Assuming that there are times and conditions when the adhesion of the existing engine is not sufficient to start the train, the Author has made out a case for the application of a booster to one of the non-coupled axles so as to be able to utilise its adhesive weight, and by applying power thereto to increase the tractive effort without causing slipping. If, however, it is necessary to use a booster it would seem desirable that the engine should be designed
Journal No. 85 (May-June 1928)
Fry, Lawford H. (Paper No. 229)
Some constructional details of a high-pressure locomotive. 314-29. Disc.: 329-43
Meeting in London on 10 January 1928 chaired by H.N. Gresley
Experimental 4-10-2 locomotive with a Brotan water tube firebox pressed to 350 psi provided steam for a 3-cylinder compound. The cylinders were formed from cast steel.
Discussion:I H.N. Gresley (329) had been unable to be present when Lawford Fry read a paper before the Institution of Mechanical Engineers: therefore this was the first time he had the opportunity of saying anything. He did not propose to go into that paper this evening, but to mention one or two facts which struck him after seeing the illustrations. First of all. Fry refers to this engine as having been tested at Altoona. I do not know how long it had been in service since these tests were carried out, and whether up to date it had run any considerable mileage. If so, it would be very interesting to know whether this engine was working in a district where the water is good or bad, and whether there had been any great accumulation of hard scale in the 4-in. tubes of the firebox. If there had been such accumulation of scale, had there been much difficulty in its removal, because, undoubtedly, scale cannot be allowed to stop there in tubes subject to a pressure of 350 psi, and with very high temperatures if dirt were to accumulate in those tubes there would be grave danger of the tubes bursting owing to over-heating. Another question which he should like to ask Fry is this. He did not mention what the cylinders are made of. Are they made of ordinary cast-iron, or are they made of cast-iron having a higher tensile strength than that usually used in cylinders, or are they made of cast steel? I have heard of cast steel cylinders being made in America. I have never seen any in Britain, but I think our steel founders would have some considerable difficulty, and possibly a few "wasters," before they could cast successfully a set of locomotive cylinders consisting of three cylinders and three steam-chests, and with all the complication of parts in a steel casting. I know from my own experience that it is difficult enough to make three cylinders in one casting in cast iron. That has been our practice in Britain for many engines for some time past.
I am rather surprised, I must say, at cast steel cranks. I have never seen cast steel used in the crank axle. I agree that it is not used for the shaft or for the pin, but it would be interesting to know what class of steel is used for the webs of these cranks. We have difficulty in Britain with axles with much lesser loads on the cranks than the cranks in this engine are required to deal with, and we do have broken cranks; and what is more difficult, we have cases of the pins and shafts getting loose in the webs. To overcome that, I have found it advisable to make the webs of a much harder steel than the shafts, and we are using steel giving a tensile strength of about 48 tons per square inch, and I am contemplating using even harder steel for the webs. I find that if the softer grades of steel are used, after some considerable time there is a tendency for the pins to get slacksay one inch or so inside the web. Cranks are always " breathing," as we call it-bending a little bit-and it is this continuous bending every time they go round which tends to make the pins loose for a certain portion of the way into the webs. On taking to pieces cranks that have been in service for some time, I find clear indication that there has been very tight metallic contact between the pin and the web for, say, four inches in a 5-inch web; but for the inch nearest the end there is indication that it has been slack.
It would be interesting if Fry could tell us whether they have had any considerable experience in America with crank axles of which the webs are made of cast steel. his data as to fuel and water consumption is expressed in terms of indicated horse-power. I venture to think that a much better basis for making comparisons between locomotives is drawbar horse-power, and that, of course, can only be obtained in a dynamometer car. There is a dynamometer, of course, at Altoona, and I should like to know the ratio between indicated horse-power and drawbar horsepower taken at various poswers. That, of course, gives the internal resistance of the engine, and we get rather confused in the comparisons made between the performances of different engines because of this difference in the bases upon which the comparisons are made.
The Author's response (taken out of sequence
herein): The President called attention to the fact that the figures I gave
were obtained on the Pennsylvania Railroad testing plant, and asked what
service the locomotive had seen. The locomotive was tested on the plant in
October, 1926, and after corning off the plant it was put into experimental
service on a considerable number of important American railroads, working
its way across the Continent to San Francisco, where it was there converted
into an oil-burner, and was tested on the Southern Pacific. In every case
the results in service confirmed the figures obtained on the testing plant;
in fact, the drawbar pull obtained was rather better in service than that
shown on the testing plant. In going across the Continent in that way, the
locomotive had to use a very large variety of feed-waters, and while there
is a good deal of feed-water purification, still the purified waters in many
cases have a tendency to foam very badly. One of the points that was always
doubtful in the minds of the locomotive engineers who were using bad water
was how that boiler would perform; whether the tubes would scale up and whether
the boiler would foam. The solid water coming from the barrel down into the
water space frame gave a good circulation, and there was no tendency to foam,
and the rapid Circulation of the water tended to keep down deposit of scale
on those tubes. It is the practice, as Lelean has pointed out, in America
to use arch tubes very largely, and where that is done it is necessary at
intervais to clean those tubes out. They are cleaned outI am speaking
now of the regular boilerby a small turbine, which is operated by steam
or compressed air and run through the tubes. The water-tube firebox tubes
are turbined, but it is found that it is not necessary to turbine them quite
as frequently as the arch tubes in the regular boilers, Evidently the rapid
circulation in the side tubes retards the deposition of scale. I did not
point out, when describing the drawings, that at the base of each tube is
a wash-out plug which enables inspection of that tube to be made. Actually
those plugs are not used in washing out tlie boiler. The headers on the two
top drums arc opened, and that enables a man to get into the drums, which
are 26 inches in diameter, and run the turbine down the tubes; Then the scale
which falls to the bottom is washed out from the regular wash-out openings
in the hollow cast steel mud ring. I cannot give an exact figure for the
miles run before this operation becomes necessary, as of course it varies
very considerably with the amount of scale in the water. My recollection
is that about six weeks elapses before turbining in the bad districts.
Gresley raised a question as to the material used for the cylinders. These are of cast iron, and they form quite an intricate casting, and it is very much simpler to make in cast iron than it would be in cast steel. The cast iron used is tlie regular grade employed by the Baldwin Locomotive Works for their cylinders. We have been giving considerable attention to the quality of cast iron, and by increasing the temperature of pouring we are getting improved results in tensile strength ,and fluidity in the cast iron. The crank axle was mentioned, and Mr. Gresley expressed surprise at the cast steel webs. The steel is about a 0.30 per cent. carbon steel with a tensile strength of approximately 35 tons to the square inch. We have made a considerable number of four-cylinder crank axles in which we used cast steel, and in these we combined the two inner webs and the axle piece, making a seven-piece axle instead of the ordinary nine-piece axle for the four cylinders, a sort of Z-shaped cast steel piece curving clown from the one pin to the other, and we have had no trouble with them. This engine has run, I suppose, 40,000 miles, which is not enough, of course, to show any difficulty if the axle is properly made, and so far it has revealed no trouble with the steel casting, The President called attention to the fact that the figures as to coal consumption are based on indicated horse-power. I quite agree with him that drawbar horsepower is the proper criterion, and that is what the transportation man is interested inthe drawbar horse-power delivered by the locomotive. The dry coal consumed runs from 2.4 lbs. up to 3.3 lbs. of coal per drawbar horse-power per hour.
J. Clayton (331): I am sure it is with the greatest of pleasure that we see here once again Mr. Lawford Fry. Many of us who knew the Institution in those earlier days when he was an enthusiastic member, remember with gratitude the work he did, as our President has posinted out, for this Institution, and I should like on your behalf to welcome him here once again and thank him for the work he has done for the locomotive. Mr. Lawford Fry's tables of comparisons of the locomotive are well Irnomn and have been much used. May I say, respectfully, that the shortness of the Paper was somewhat disappointing, as we had hopcd for a good deal more information about the details of the engine, though what the Author has shown us was very interesting. His recent paper hefore the " Mechanical lingineers " was very useful, but as pointed out, they were results obtained on a test plant and it would be more interesting still if we could be assured that thcse figures may be expected in serviice. With regard to one or two points about the design, I should like to know how the tubes are fixed into the drum. Are the drums large enough to enable a man to get down with a tool in order to expand the tubes into the drum? Perhaps they are, but it was not clear from the illustration. I should also like to ask if the cylinders are of cast steel, and if so, are they lined with cast iron? It looks such a beautiful casting that I am inclined to think it must be of cast iron, Another point I want to ask is this: with regard to the crank axle, I am surprised to find that Americans are brave enough to make crank axles with balance weights on the crank webs. Experience seems to show that placing them there, although pretty on paper and in theory, in practice it has a tendency to make the pins loose, and moreover, to save weight, the best way is to put the balance weight into the wheel. It is also noticeable that separate valve gears are used for each cylinder. There are one or two peculiarities about the diagrams also, especially with regard to the high pressure. This is very high on the line of admission and falls abruptly to the point of cut-off. I should also like to ask if the steam is superheated between the high- and low-pressure cylinders.
Lawford Fry's response: The water tubes for the firebox are fixed by beingrolled and belled into the water space frame, and into the upper drums they are rolled, belled and welded. The placing of the balance in the web of the crank axle was discussed. Theoretically, one can balance with less weight if the balance is not placed in the extension of the crank axle, but in a large locomotive with a weight of 30 tons or over on the axle, and a 63-inch driving wheel, it is extremely difficult to find space in the driving wheels for all of the balance weight that we would like to get in. Therefore the crank cheeks were extended and utilised to balance part of the weight.
H. Chambers (332): I have been very interested in the boiler proportions, owing to various designs that have gone forward recently through my hands. I had time to count up the number of flue tubes in this three-cylinder compound engine, and I think I am right in saying there are 50. There seems to be in American practice to-day a tendency to enlarge very much upon the proportion of superheating surface as compared with what we have been used to in this Country [Britain], which is about 42 to 45 per cent. of superheater free area to the total free area of the tubes. The 50 flue tubes must greatly increase the superheating surface for the boiler. I should like to know the exact proportion if Mr. Fry can give it, and also any comments he may make with regard to the steaming of the boiler, because it seems to me that to give such a large proportion of superheating surface in a boiler involves a tendency to reduce unduly the evaporative heating surfaces of the boiler itself, and after all, we have to produce the steam before it can be used usefully, and one of the first essentials is a free steaming boiler. One of the details with which I was rather struck is the connecting rod for the inside high-pressure cylinder, which has a marine type big end, but I did not notice any attempt at lubrication. I should like to know what lubrication is provided for the big end, and whether I am right in assuming that there is some type of floating bush provided in the big end. I congratulate Mr. Lawford Fry on providing a separate gear for each cylinder, as I think that is the right thing. I do not think I quite agree with the remarks made by Mr. Clayton with regard to the balancing not being correct when provided in the sweeps of the crank axle. Perhaps Mr. Fry can explain. There are advantages when the balance weight is-in the same plane as the parts to be balanced if possible. There is one feature which is objectionable from a shed point of view; when the big end is stripped, it is very difficult for the examining fitter to see the inside of the big end pin due to the position of the balance weights at the opposite end. Another point that does not seem to me very good practice is the axle, for it is apparently quite a rough finish, Any built-up axle should be very carefully examined while in service; for instance, Mr. Gresley mentions trouble with regard to the big end pins getting loose. It has been the practice on the L.M. & S.R. to finish very carefully the face of the big end pins and the barrel portion, which provide the axle box journals, dead flush with the sweeps, and by this means an examining fitter can decide immediately whether any slackening or disturbance has taken place. With regard to the other details which have not been very greatly touched on, I should like to ask Mr. Fry whether he can tell us anything with regard to the lubrication of the cylinders and piston valves. With these high-pressure boilers and with the larger proportion of superheating surface, the tendency is, I think, to get a very much increased superheated temperature. Has Mr. Fry experienced any trouble with lubrication? Or may I put it this way: has he experienced any trouble with carbonisation in the cylinders, and if so what steps has he taken to overcome that? I may say that on the Midland Division of the London Midland and Scottish Railway, we have mechanical lubrication on all superheated engines, and carbonisation has been reduced to a minimum, due to the provision of a very reliable and efficient air valve; in fact, carbonisation is a thing of the past.
Lawford Fry's response: Chambers inquired about the lubrication of inside main rod. The rod was originally made with a fixed bushing and is so shown in Fig. 8. It has since been changed and a floating bushing applied. Grease lubrication in accordance with regular American practice is used.
W. Cyril Williams (333): I would like to know the temperature of the superheat and what kind of packing is used. also the length of boiler barrel and the temperature of the gases in the smokebox. It would be interesting to know how the tubes are expanded into the drums. As the President has remarked, it is how the locomotive functions on the road that counts. There are certainly no stays in the firebox, but there are innovations, and the question is, are these going to stand up to the erratic demand the cylinders of a locomotive make upon a boiler? It occurs to me that, while the present design has been worked in on a locomotive of orthodox type, another shape of locomotive might enable better results to be obtained, such as the Garratt or similar type of locomotive. Such an engine has a cradle into which perhaps a better design of water tube boiler could be fitted.
Lawford Fry's response: Williams asked about the steam temperatures, and I will refer back to the original test report, in which-the steam temperatures run from about 600 up to 680 degrees Fahrenheit. The boiler tubes are 23 ft. long, the firebox 138 inches, or I I ft. 6 in. long, and there is about 5 ft. 6 in. combustion space. The temperature in the smokebox ranges from 519 degrees Fahrenheit to 645 degreesapproximately what one would get with a similarly proportioned boiler of conventional design.
H. Holcroft (334) I would like to amplify a few of the points already touched upon by various speakers, and the first thing is the boiler itself. We have had a description of the boiler given us, but nothing has been said about the boiler as a structure. I should like to know whether it is, so to speak, self-contained? Can it be lifted as a unit without any risk? There is also the question of enclosing the firebox tubes. Asbestos lagging is shown, and also fire brick, and I should like to have some information as to the life of the insulation, and whether any heavy renewals are found to be necessary in the firebrick or asbestos. Another thing that strikes me is, how is the examination of the boiler to be madewhether the interior of the tubes in the firebox can be examined, and also the various drumsbecause in this case there is a certain amount of danger from burst tubes which one does not get with an ordinary type of firebox? The President had touched upon the question of the crank axle, and I may remind you that we had a very interesting paper on that subject at the Manchester Centre by Shawcross, in which the author went very fully into built-up crank design, and one of the things that he dealt with was the shrinkage allowance, and how that varied with the different classes of steel used. In order to get a good grip on the axle, one must either have plenty of metal in the web round the pin or a high tensile steel, and the shrinkage allowance has to be proportioned so that the elastic limit is not exceeded. At the same time, it is necessary to keep down the dead weight of the crank axle, because it is not spring-borne, and in designing it one has to consider whether it can be reduced either by putting the balance weights into the wheels or by extending the webs as a counterbalance or by choice of the material used. Cast steel does not seem to be a material that lends itself to reduction of weight in that way. Mr. Clayton touched on the subject of the valve gear, and the question arises as to whether a combination of levers would not be simpler than a third gear. The levers as now used on the three-cylinder engines are in conjunction with the 120-degree setting of cranks, but it is quite practicable to adopt the same method with the 135 degree setting, merely by an alteration in the proportions of the levers from 0.5 to 1 to 0.7 to 1. If it is necessary for the high-pressure cylinder to have a different rate of cut-off to the low-pressure it can be done by varying the proportions of the levers from the ratios given so as to modify the travel, and by an alteration to the lap of the valve. The indicator diagrams show that the horse-power developed in the high-pressure cylinder is approximately equal to either of the two low-pressure; that is to say, that each cylinder develops about the same horse-power. It is usual in a compound engine for the horse-power to be divided equally, or as nearly as possible equally, between the high-pressure antl the low-pressure stages, and it is rather interesting to hear that in this case only one-third of the horse-power is developed in the high-pressure. Nothing has been said about the degree of superheat used, or whether there is any receiver between the high-pressure and low-pressure cylinders, that is to say, whether the steam goes direct from the high-pressure exhaust into the low-pressure steam chest or not. I should also like to consider the question of building this engine as a high-pressure engine, as opposed to a compound. The cut-offs, as you have seen, have all been very long, and I wonder whether it would not be better to have a simple engine with a shorter cut-off. It would then have the benefit of the better smokebox action arising from the six beats per revolution in a slow speed engine. Also it would give a better turning moment, because with a 120° setting the cranks are equally spaced round the wheel, instead of which they are 135° and 90°. Also there would be a better adhesion value for the tractive effort; that is to say, a higher tractive effort would be obtained in relation to the available adhesion with a simple engine.
Respone Holcroft had asked as to the strength of the boiler, whether it could be lifted and handled. The attempt, in designing the boiler, was to make it thoroughly solid, so that it was not only strong enough to be handled itself, but would give support to the locomotive. I pointed out that the drums were extended forward, and riveted to the top of the boiler barrel, and at the back of the drums there are four water tubes run down from the drums to the water space frame, and then steel sheets also tie the drums to the water space frame. The side tubes also give a stiff connection between the water space frame and the drums. While speaking of this, I might deal with the question asked as to the construction of those drums, which are 26 inches in diameter. The seams are hammer welded, and then, in order to comply with the requirements of the United States Federal Government, butt straps are riveted over the welded joints. I doubt very much whether that is actually necessary, but the Federal inspection requirements for locomotives require that to be done. I might say that the tubes were made by the National Tube Company, and we asked them to mark the point at which the weld occurred. When we got the drums and examined them, if it had not been for that mark, we could never have told where the weld came: they had made such a nice job of it. Holcroft raised a question as to the proportions of the cut-off and the distribution of horse-power in the cylinders. The cylinders each have their own valve motion, but all three motions are operated by a single power reverse gear, so that the ratio between the cut-offs for any position of the reverse gear is settled in advance. This locomotive, being a freight locomotive, has the gears arranged so as to give as nearly as possible equal distribution between the three cylinders for the range of speeds over which a freight locomotive would be expected to operate that is, up to about 22½ miles an hour there is almost equal distribution between the three cylinders. It might be possible to set other cut-offs which would give a higher cylinder efficiency, but there are a number of practical considerations that come in. With a locomotive of that size it is desirable to distribute the power as nearly as possible equally between the three cylinders, so as to keep away from excessix-e sizes in any two rods. Locomotive design, like all engineering, is a compromise. We have to choose between extreme efficiency in the use of the steam, and practical dificultles. The design was thought to be about a happy medium, and results seem to have justified it. The same point applies to the reason for choosing compounding and not three high-pressure cylinders. With high-pressure steam, high expansion is desirable if the full efflciency of the steam is to be obtained, and if we use a single expansion cylinder and a short cut-off, the variation in piston pressure through each cylinder becomes considerable, and then for a given mean torque we have to have an excessive weight of piston and rods to take the high pressure at the beginning of the stroke. It is a balance between practical advantages and the efficiency in the use of the steam.
W.A. Lelean (335): Dealing with the boiler itself, as one speaker has already pointed out, it is the extraordinary novel feature of the boiler firebox that appeals to one first. The Author referred to the boiler being used as a structure to carry the engine, which is fairly common American practice, but we do not quite agree with it in this Country. I think there is much to be said for the retention of the normal structure of locomotive barrel with the tubes going through it. The chief difficulty which I foresee, and which other members have touched on, is the cleaning of the tubes forming the firebox sides. The circulation, no doubt, is pretty severe, but none the less I should imagine that the tubes would get choked up very much between the foundation ring and the drums. When, copying the American practice, we introduced tubes for supporting the brick arches, it was very strongly insisted on that the very greatest facilities should be given for cleaning these out, with the result that we have provided seatings with covers opposite the end of every tube so that the covers can be removed at any time in the running shed to re-expand the tube inside; and each of these covers is provided with an ordinary \\ashout boiler plug, so that the tube can be thoroughly scoured every time the boiler is washed out ; without this special attention those tubes are likely to give trouble. I could not see, from the illustrations, whether there was any provision opposite the end of each tube so that one could get in to re-expand the tube, or whether, as someone asked, a man had to be put inside to expand the tubes. Certainly there seems to be no facility for washing each individual tube from the drum end, so perhaps Mr. Lawford Fry would tell us what is done in that respect. With regard to the crank, I think I must agree with Mr. Clayton as to the place to put the balance weight, for the reason that the crank is not spring-borne, as Holcroft has pointed out, and therefore it seems undesirable to put more weight in the centre of the crank axle than one can help, or else there is a liability to loosen the crank webs. For some very heavy four-cylinder engines, with 28 tons per axle on each of the coupled wheels, for which we now have designs in hand, the suggestion has been made that the outside crank web and the journal shall be made in one piece, and that the centre portion of the axle shall be of the ordinary oblique form ending in the crank pins which go into the webs. The firm who are interested in designing this engine are quite satisfied that they can make a thoroughly sound job of it, and from the experience on railways we have had of the behaviour of this firm's cranks, we think they can be relied on to make them tight. On the other hand, we have heard of identically the same cranks made by another firm which have proved a complete failure. The point I want to make is that there is a great deal in the experience required as to the amount of shrinkage required for making a built-up crank axle, and locomotive builders may not be quite successful the first time they try. Fry did not favour Lelean with an individual response.
E.C. Poultney (336): I had the pleasure of hearing Fry's paper read before the Institution of Mechanical Engineers, and it was there brought out lery clearly that the compounding of this engine had been fully justified by the excellent steam rates in the cylinders; but there is a point about the performance of the boiler which I should like to raise, and that is this, that in examining the plot showing the boiler efficiency against the firing rate I rather hold the view that the boiler does not perform very well, and it seems to me that if that is so it is a pity, and also a point that must be rather seriously considered, because the engine undoubtedly utilises the high-pressure steam to great advantage, but in order to generate the steam at 350lbs. pressure a water-tube firebox has been adopted, and although the firebox has a very large grate and a very large volume! yet the efficiency seems to fall off somewhat rapidly. It IS never very high, and falls off rather quickly, and compared with other boilers having the normal type of firebox the boiler does not appear to function very well. I made a note of an engine tested on the same plant, the Pennsylvania K-4-S Pacific with the ordinary firebox, in which the proportion of grate area to heating surface is 75, and at a rate of firing of 70lbs. of coal per square foot of grate the boiler efficiency is 78 per cent. The Baldwin locomotive has a heating surface grate ratio of 79, and when firing 7oIbs. of coal per square foot of grate the efficiency is only 63 per cent. It seems to me that if the boiler can be made as efficient as the normal type of boiler, then the engine will be even more efficient than shown. I think that is a point that ought to be considered, and it may, I suggest, be due to the water-leg type of firebox. I am not quite sure on that point, and I should like to have some information as to whether it is thought that the water-tube firebox can be as efficient as the ordinary type of firebox. It is a matter of some importance, because I think we shall have to use the water-tube idea of construction for the utilisation of very high steam pressures.
Response:. Poultney called attention to the boiler efficiency. In showing the figures for coal consumption, I said that the boiler efficiency was what we would expect to obtain from a well-designed boiler of conventional design. I have checked these figures for boiler efficiency with the Pennsylvania Railroad tests of the Pennsylvania locomotives, and when using the same grade of coal the boiler efficiency of locomotive 60,000 runs very parallel with that of the Pennsylvania locomotives. The efficiency of combustion drops from about 86 per cent. at the low rates to about 65 at the higher rates, and the whole boiler efficiency at 50 lbs. per square foot of grate per hour is about 67, and drops down to about 52 per cent. at the higher rates. This is, as I say, what we should expect from a well-proportioned locomotive of conventional design. The water tube firebox was designed as a constructional feature to avoid flat stayed surfaces in connection with steam of 350 lbs. per square inch. It was not thought that it would give greater boiler efficiency. At first sight it might be thought that the greater radiating surface exposed by the tubes would give greater efficiency, but one has to remember that there is only so much heat produced, and if a larger proportion of it is taken up in the firebox there is less left for the tubes to take up, and the heat entering the tubes at a lower temperature is absorbed with less efficiency. Therefore it about balances out. With a large radiating surface one gets more heat taken up in the firebox, and less is left for the tubes to absorb.
W.J. Tomes (337): I should like to ask the Author what kind of circulation is obtained between the boiler barrel and the cast steel foundation ring. Could Mr. Lawford Fry give us some particulars of how the tubes fare in service? Supposing one of the tubes were to burst, how is it taken out? Reference has been made to the incrustation of the tubes, but from my experience of American railways they do not hesitate to soften their water at watering stations; so I take it that they have very little difficulty with incrustation. I remember we tried the " Hornish " cleaner, which in itself was excellent, but it failed in our case for the simple reason that the blow-off valves were never made proper use of, and it was not until some time afterwards that we found out the reason, viz., that the drivers thought that they would have to run longer between shed clays. I must say that there is very much to admire in the design of the boilers that the Americans have lately adopted, and with others,
Response. Tomes asked about the circulation in the tubes, to which I have referred, and inquired what mjould happen if we burst a tube. I am glad to say that I cannot answer that question. It is our thought that a burst tube would be much less disastrous than a burnt crown sheet, but we have not tried it out in practical work!
N.A. Shove (338): The point I want to ask Mr. Lawford Fry is whether any other designs of a water-tube boiler were considered when this engine was being brought out, because, after all, this boiler is practically an ordinary locomotive boiler with water-tube firebox, and it struck me that perhaps they had considered some other type of watertube boiler at the time-something after the Stirling type, for instance, or the Babcock & Wilcox some departure altogether from the locomotive boiler. The other point I should like to raise is whether the Author can give us some constructional details of the two water drums on the top of the water tubes. What is their form of construction, the thickness of the plates, and are they riveted or are they rolled?
Response. Shove referred to the use of other designs of watertube boilers. This water-tube firebox is, of course, a modification of the Brotan design, which came out many years ago. There are in experimental use or under construction quite a number of other types of water-tube boilers. Some, such as the Delaware and Hudson R.R., and New York, Newhaven and Hartford R. R., have a water-tube firebox only, but rather more complicated than the design I have shown, and they are working fairly satisfactorily. There are, of course, other designs which are being built which are conlpletely water-tube boilers. I must say that the water-tube firebox with the fire tube barrel makes a strong appeal to me from the constructional side of the locomotive, and I was interested, in talking with Mr. Wagner of the German State Railways recently, to find how much weight he laid upon that where he was designing a purely water-tube boiler. He tried to bring the whole thing into the shape of the regular locomotive boiler, and so provide a longitudinal barrel to which he could tie the frames, and which would give him a backbone for the whole locomotive. Speaking elsewhere, I have called attention to the fact that the electrical engineers, in designing their earlier electrical locomotives, did not appreciate the strength which had been given by the locomotive boiler, and they took the same locomotive frames and put a lot of electrical machinery on to them, and found that they had a great deal of trouble because they had not got the boiler to support the frames.
Gresham, J.N. (Paper No. 230)
Vacuum braked freight train trials (Companhia Paulista de Estradas de Ferro, Brazil, 19261927). 353-74. Disc.: 374-88.
Meeting in London on 1 March 1928, chaired by A.M. Bell.
Vacuum braked trials were conducted at the request of the Paulista Railway Company, Brazil, which owned 1,300 km of track, 500 km. of which are 1.60 m. gauge of this only 44 km were double tracked. The system operated in the State of Sao Paulo, connecting up with the Sao Paulo Railway at Jundiahy.
Mr. O. Bulleid : We thank the Author for his interesting Paper on a subject in which all railwaymen are interested. It is, however, very difficult to criticise the Paper when we have not had the goad fortune to have the diagrams in our hands before the meeting.
The brake question is primarily the stopping of a train from a given speed in a certain distance. Mr. Gresham has given us many interesting figures, all depending, of course, on the gradients with which he has been dealing and which, obviously, are very se\;ere. Experience in England with trains of 60 to 100 wagons braked throughout has given us considerable knowledge of how to handle the brake, but unfortunately we have not been able to work the 20-inch vacuum over 60 wagons. I feel a little sorry that a 16-inch vacuum was used in the Brazil trials on the ground of difficulty of maintenance. It seems to me that the sacrifice of 4 inches of vacuum in the brake, is. a rather expensive sacrifice of power when it can be overcome by greater attention to the joints, couplings, etc. When making our lmg brake trials in England with 100- wagon trains we had considerable difficulty in stopping the train without shock; and were only able to qyercome ihe shock when stopping at low speeds by inserting reducing washers with much smaller holes than Mr. Gresham used. If I remember rightly, our washers were 5 / 3 2 for 21-inch cylinders and 9 for an 18-inch cylinder. Those sizes were very carefully arrived at by experiment to give a more or less equal feeding of air into the cylinders throughout the train. We have made many experiments and we came to those figures as the result of the tests. The reducing washer has the advantage of equalising the application of the brake, but it also has the serious disadvantage of making it slower to release; and this latter had the indirect effect of making it extremely difficult to reduce speed from low speeds. If on a train at 20 miles an hour a brake application was made at all, and it was then desired to release the brake to regain speed, we had considerable difficulty in so doing. The trains experimented with in Brazil weighing 1,500 tons were heavier than those used in experiment in England, but the Ioo-ton wagon train of the L.N.E.R. was longer and possibly, therefore, the difficulties in England were greater than the difficulties which were experienced in Brazil.
In conclusion, I think we should congratulate Mr. Gresham for giving us particulars of such tests because there is very little information on that subject available. It is very rarely that information is published about emergency stops, and it is certainly useful for us to have figures of that kind ready to hand.
Bond, R.C. (Paper No.231)
Fundamental considerations in the design of locomotives. 389-401. Disc.: 402-6.
Factors influencing tractive effort:
weight on coupled wheels.
diameter, stroke and number of cylinders.
diameter of the coupled wheels.
working boiler pressure
amount and disposition of heating surfaces.
quality and calorific value of the fuel burned.
The performance of a locomotive depends not upon any one factor, but on a number of related dimensions, and the tractive effort and draw-bar horse-power are limited not by the average of these related dimensions, but by the weakest of them. Every part of the engine should be carefully proportioned to all the other parts. The application of the results of practical tests as a means to this end is of the utmost value, but it must not be forgotten that calculations and estimates, while very necessary, are only the beginning ; the final test is in traffic, and the most carefully designed engine may be wonderfully improved by some slight alteration made as the result of practical experience on the road.
Discussion: A.C. Stamer (402-4) had drawn attention to the fact that very little has been said in the Paper on the question of steam distribution. I fully realise the vital importance of this matter, and the effect which it has upon locomotive performance, so much so that I felt it was essentially a subject for a paper in itself and could not therefore adequately be dealt with in the time at my disposal for the present Paper. There can be no doubt that the excellent results obtained with the Royal Scot outlined briefly above are due to the combined and mutually reacting effects of a good boiler generating steam at 250 pounds per square inch, and the ample cylinder capacity enabling the high pressure superheated steam to do its work at an early cut-off, made possible by long travel valves giving a good distribution and a very free exhaust. Mr. Robinson has raised,
Clayton, J. (Paper No. 232)
Engine failures. 409-24. Disc.: 424-31; 610-22 + 10 folding plates. 6 diagrs., table, 9 facsim. forms.
The paper notes the reduction in the number of locomotive failures on the S.R., since 1923.
The object of this Paper, therefore, will be to discuss the various methods adopted by our railways, particularly the four groups in this Country, for obtaining the information necessary with regard to engine failures, and to show how the details are collected, recorded and classified, and to indicate how this is used in the machinery of railway administration to promote maximum efficiency. Those accustomed to use or deal with machinery or mechanism of any kind, even though it be only a " humble push bike " or " small car," do not require to be told that care and good treatment make all the difference to the way in which they run and the cost of running. Neglect a slight rattle or knock from a loose nut and the result may soon be costly or even disastrous. The proverbial " stitch in time " is never so true as when applied to a piece of machinery. So in connection with the locomotive driving and maintenance, the engine should receive thought and care in handling and tending. But after all, assuming that the driver does his best and the shed staff give all the attention possible to maintain the engine, things happen in service even when the best has apparently been done. It is understood that there is a good deal done to all engines in order to keep them fit for work, both by the driver and those who carry out the ordinary shed repairs. Long experience of the running of engines has indicated that certain parts require regular and close examination, such as cannot be given by cursory or superficial daily attention.
So most railways draw up a list of periodical examinations for the use of their running maintenance staffs, and an example of such a list is shown by Plate I. These refer to the principal parts of engines and tenders, and give the minimum time such parts may be allowed to run before receiving attention, a note at the end (u) pointing out that should experience show that some details require examination at shorter intervals, discretion must be used, while note ( b ) suggests that if the exigencies of any particular case cause the engine to be stopped for emergency work, the opportunity must be used to make the necessary periodic examination of parts whose due time is near, and so avoid the engine being out of traffic more than necessary. How important this is may he gathered from the fact that an engine out of service may be costing the company up to Lzo per day-like a horse eating its head off with no work to do. The sheds to which the engines are allocated generally keep a record or history sheet of each engine and tendcr from the time it is handed over by the works as ready for service. From this point its history begins, and the mileage accomplished is carefully kept alongside the tims at work, and as the various occasions for the examinations come round the engine receives its periodical attention. Everything done to the engine is recorded in detail, and thus its biography comes to be written and can be known ot every stage throughout its career.
Notwithstanding all this detailed attention and care, dips occiir as in the best of well-regulated families-someone negjects his duty ; a hidden flaw in metal develops ; aq pnusual strain is thrown upop some detail, perhaps from something esterior to the engine, such as an inequality in the track; a sudden change in temperature of the atmos phere ; a heavy storm of wind and rain ; a sudden check by an emergency application of the brake ; an unexpected signal check causing immediate interruption of working ; violent slipping set up by greasy or leafy rails-there are so many variables in locomotive working-and an unforeseep failure occurs. When we multiply these chances by some 20,000, the number of locomotives, say, working every day in this Country, we shall agree that machinery must be set up in order that the maximum information is available for the thorough investigation of all failures, so that :-
I . The Board of Directors or Managers may have a reliable index regarding the suitability and degree of maintenance of the locomotive stock.
2. The Locomotive or Chief Mechanical Engineer and the Motive Powrr Superintendent may have reliable and useful knowledge as to the suitability of the engines for the work they have to perform and the manner in which they are handled and maintained by the staff.
It is necessary, therefore, to clearly and logically define what is to be regarded as an engine failure or casualty for recording purposes. Here we come to a point upon which there is difference of opinion and about which there has always been much controversy. So much so that on making inquiries it is found that no two of the grouped railways in this Country have exactly the same definition of an engine failure. To illustrate how diverse:
Definitions of an Engine Failure or Casualty.
I . During the working of a train, any defect developed in an engine or tender whereby the efficiency is impaired and time is therefore lost.
the failure of an engine, after being fired, to work its train to time through any defect obvious or concealed.
2. An engine which has to give up its train owing to a mechanical defect, or inability to work its train forward involving delay will be considered as having failed.
any mechanical casualty involving deiay or which prevents an engine completing its rostererd working, even if no delay is incurred, is to be regarded as an engine casualty.
3, An engine which has to come off its train owing to any mechanical or boiler defect, even if no delay is caused, is to be considered a mechanical failure.
an engine which through a mechanical or boiler defect causes a delay to its train of 10 minutes or over to be also considered a mechanical failure.
It is difficult to say what the reasons for these fine differences are, but it may be suggested that they could all be equally covered by a simple definition, such as follows :-
" Any defect developing in the locomotive or tender after such has been prepared for work, or during the working of the train, whereby the efficiency is impaired and time lost or in consequence of which it cannot work the appointed train," is to he reported on the failure form provided.
Defects covered by the definition laid down are as pointed out reported on the form provided, and Plates 11. and 11a. show typical examples of such.
Discussion; Gresley (611-12): Gresley: "I think this Paper we have had from Mr. Clayton is one of the best I have had the opportunity of listening to, and has been of most valuable educational and instructive interest to all. Had it not been for this Centre being formed, I venture to think there are many who would not have travelled to Leeds to hear this Paper read and many would not have otherwise had this opportunity of learning of the machinery which should be employed in the recording of engine failures, which has been so excellently set forth by Mr. Clayton. There is very little indeed in the Paper to which I can take exception, and I would like to compliment the Author on the excellence of it.
Mr. Clayton has shown his examples of the forms used on the Southern Railway, classifying failures under various headings and sub-dividing them into classes of engines.
The criticism I would make in regard to the forms is that some of the headings are superfluous. I refer to the headings for axle and tyre faiIures. If a fracture of either occurs it is a very serious matter and special investigations are always made. Then there is the heading Cylinders. We do not often have broken cylinders, and this, I think, could also be omitted. The return we use on the L.N.E.R. has fewer headings, these being to cover failures most frequently arising.
Another point Mr. Clayton referred to was the periodical examinations. I want to say this, that although these may be made, I have found that difficulty arises in recording them. Cases have occurred where valves have failed, and it has then been discovered that the monthly examination has not been made for some two or three months, perhaps, whereas if the rule had been carried out the failure would not have occurred. 1 think the best method of recording is the card system, the cards to be kept in a box, and transferred to anomther box as the examinations are made ; at the end of the month perhaps three or four cards would be found left in the box, which engines had not been examined, and the matter could then be put in order by the inspection of these engines to complete the number at the shed.
The definition of a "Failure caused me trouble, and I am afraid I cannot agree with the one Mr. Clayton has proffered. It seems to me that if an engine is a minute or two late it should not be called an engine failure, even if the slight delay was due to some mechanical defect. Supposing some joint had blown out, and made it difficult to maintain steam? Even if five minutes were lost I do not think it could be termed an engine failure. Rather should the enginemen be complimented on their good work in getting the engine to its destination under difficulties. I quite agree with the card system for engine drivers reporting repairs when finishing duty, and they have this system in France. When the engine arrives at the shed the driver reports defects on a card, and this is given to a mechanic, who immediately examines the engine and writes on a card w-hich defects should be attended to at once, which should be deferred, and which are quite frivolous. He also observes any other defects which the driver has missed, and the complete list is then handed to a fitter, who attends to the repairs as required. With reference to the pooling of engines, I consider we could go in more for double-manning in this Country, but do not recommend more than two men to an engine. I refer more particularly to express engines.
Mr. Clayton objects to mechanical lubricators, but my opinion is that apart from the actual supply of oil they are most advantageous in the interests of economy. The running superintendents give me definite assurance on this point, and it is even suggested we should have shunting engines fitted with these lubricators. Springs are a great trouble, and there are far too many spring failures. Motor engineers have been studying these failures, and locomotive engineers are now doing the same. In motor cars, failures in this respect are eliminated in the high class models by the. grinding of all springs plates, which would be too expensive for the railways. If, by improving the qualities of the steel and the design of the springs, the formation of surface cracks could be eliminated, I think failures would decrease. If you make an examination of springs, you will be surprised to find how many are badly designed.
I am afraid I have taken up a lot of time, but failures of locomotives is a subject on which much time can be spent, and anything that can be done at this Centre in Newcastle in regard to improving results so far as engine failures are concerned you may be sure will be of great benefit to the Institution, and to the railways.
Journal No. 86
Manufacture of superheaters. 454-60.
Commentary on a film
Parker, G.C.R. (Paper No. 233)
Are screwed smoke tubes worth while? 461-4. Disc.: 464-89.
Case, Charles (Paper No. 234)
The organisation of a locomotive running department in the Argentine republic. 470-536. 37 figs. (illus., plan. diagrs.)
Figures include plan of sttraight-through shed at Rosario. In part the paper showed the methods employed to control locomotives, including the forms used for reporting and compiling data, and in part means used to increase the productivity of both locomotives and enginemen. Breakdown fascilities included the provision of housing en site for the crews at Rosario. As an instance of the distances which can be attained by through running of engines without serious locomotive defects, a trial was once made on the Central Argentine Railway of a run with one engine between Retiro and Tucuman, 1,156 km.
Hadfield, Robert, W B Pickering and S A Main (Paper
Recent developments in alloy steels. 547-88. Disc.: 588-608. 24 figs. (ilus., diagrs.)
Notably heat resistant, corrosion resistant and high tensile steels. Many of the key applications were for items like turbines, aircraft and chain grates for electricity generating stations. The use of alloy steels in locomotive engineering, as in other fields, must depend largely upon the results of trials, in those cases where the special characteristics possessed were called for. Discussion: F.H. Eggleshaw Although firehole deflectors made of heat resisting steel gave longer lifc than ordinary mild steel, the price of heat resisting steel deffcctors was against their general use. As regards corrosion resisting steels, one point of great interest was that a steel with 0.25% copper content produces a metal with greater resistance to corrosion, Experience with the largest LNER passenger and goods engines fitted with nickel-chrome high tensile steel connecting, and coupling rods had produced very good results, with a considerable reduction in reciprocating and rotating weight.
The Chairman (G.A. Musgrave 588-9): With regard to the baffle plate, which is a typical use of this heat resisting steel, in this particular instance it proved to give a much longer life than the ordinary carbon steel plate. The chief factor of course is cost, although one cannot always condemn an article because it is dear; it may prove to he very much cheaper in the end owing to length of service it gives over a similar article at a much cheaper cost. I am afraid that argument is often lost sight of. The .Authors mentioned cases where this material is welded by either oxy-acetylene or electric arc: what class of metal did they employ for this purpose. He also asked what their opinion was of vanadium steel, whicli was much used in America. The reply was that vanadium is in much more general use in steel manufacture in America than in this Country. Experience here has been that its advantages do not lie so much in any physical properties which it confers per se upon steel, but rather in its action as a scavenger of undesirable impurities. Here it is more generally preferred to remove those lmpurities by careful attenrion to the steel making process. There are special cases, however, as in high speed steel, where vanadium is used as an additional alloying element with advantage. The coefficient of expansion of these new steels varies in the different types, but over the range from ordinary teniperature to ~,ooo~Cis. usually higher than that of ordinary steel, and varies from 13 to 20 millionths per degree centigrade.
E. Windle (590-1) asked whether non-corrodible steels would be suitable for locomotive fireboxes, where there is the heat of the fire on one side of the plate and the scaling and corrosion on the other. Could one of these special steels be substituted for copper in the case of the firebox stays? The initial cost would apparently rule out its use for boiler tubes, but would there be any objection to the welding of an end of this steel on to the firebox end of ordinary steel tubes, where both burning and corrosion are the most severe? With regard to the high tensile steels, is there any prospect of their being rendered more suitable for forging or treatment in the ordinary smiths fire, and by the type of workmen employed in general engineering works; or is it advisable or imperative that when these steels are be.ing worked it should be under the supervision of a metallurgist? The possible use of special steels for firebox stays would certainly appear to be grounds for a practical trial, which is the only way to settle the matter definitely. We should be very glad to co-operate to that end.
Journal No. 87
Smith, W.G. (Paper No. 236)
Some features of the mechanical and electrical equipment of the Port of Manchester. 624-44. Disc.: 644-7.
Presented at Sixth Ordinary General meeting at College of Technology, Manchester on 30 March 1928.W.G. Smith was the Chief Mechanical Engineer of the Manchester Ship Canal. Described the Manchester docks, cranes, capstans, grain handling gear at Trafford Wharf, hydraulic pumping stations, Barton Aqueduct, coal handling plant, the railway and its 72 locomotives.
Brown, Herbert (Paper No. 237)
High pressure locomotives. 655-86. Disc.: 686-92. + 2 folding plates. 25 figures (illus. and diagrs.)
Presented following the Annual General Meeting on 18 May 1928. Reviewed experimental high pressure boilers for steam locomotives, including ones with closed circuits then described an experimental Swiss Locomotive Company 2-6-2T with high pressure (850 psi) water tube boiler and a three-cylinder uniflow single expansion engine with poppet valves with the drive taken through a jack-shaft. The locomotive was tested with a dynamometer car on the Swiss Federal Railways.
In the discussion J. Clayton (p. 689) asked how routine maintenance would be tackled; the weight of the boiler and the exhaust pressure.
E.W. Taylerson: (pp. 691-2) I was very interested in hearing Dr. Brown read his Paper on the high pressure steam locornotive, and consider he is to be congratulated on it. Judging by some of the questions put to the Author, the successful use of high pressure steam, coupled with the departure from orthodox design, appears to be novel to-day. It may not be generally known, however, that many of the principles adopted, as shown in the lantern slides, are nor new, but are the elaboration of the patents of Jacob Perkins, the pioneer of high pressure steam, between the years 1827 and 1835, records of which still exist in the Patent Office in London. Perkins demonstrated that steam could be handled and controlled with safety at pressures ranging from 500 to 1,500 lbs. per sq. inch. Of his patents I refer in particular, firstly, to the sealed tubes shown on one of the slides, representing a « three unit" high pressure boiler, in which the sealed tubes containing the distilled water transmit the heat to an intermediate boiler; and secondly, to the "uniflow" exhaust of the 2-6-2 high pressure locomotive recently constructed which he explained in detail. The sealed tube was patented by Perkins in 1831 and used in several of his patents onwards, including the steam gun, while his "uniflow" engine was patented in 1827 and used successfully in high pressure compound pumping engines in connection with the excavations for St. Catherines Dock, London. It seems, therefore, rather unfortunate that manufacturers in this Country have not progressed in the past century with the patents of Jacob Perkins, instead of leaving it to others to continue these early experiments and demonstrate what is now being done in the use of high pressure steam, when all the early experiments and patents originated in this Country.
The Paper was of particular interest to me personally, because my late father had two "Perkins" high pressure stationary engines erected for the Sub-Wealden Gypsum Co., Ltd., now the Gypsum Mines, Ltd., of Mountfield, Sussex, and one for the Dorking Greystone Lime Co., Ltd., Betchworth , Surrey, between the years 1872 and 1876. The former were of 200 and 32 h. p. respectively and the latter 22 h. p., all fitted with cast iron tappet valves and working at pressures between 400 and 500 lbs. per sq. inch, supplied by tubular boilers constructed of wrought iron elements screwed together with special nipples and tested to a hydraulic pressure when new of 2,000 lbs. per sq. inch. These boilers had an average life of 30 years in use, which I give as a matter of history. But the point of interest is, I think, if high pressure engines were used successfully so long ago in commercial undertakingsand our railways fall within this categorywith boilers constructed of wrought iron, how much better off is the engineer of to-day, equipped as he is with all tbe new types of steel from which to select suitable materi a], together with the advantages of electric welding, unknown in those days, in order to ensure that the boiler is finally watertight under high pressure?
The improvement of the steam locomotive as we know it to day, especially in this Country 'with its limited loading gauge in comparison to other countries, undoubtedly rests in the use of steam at pressures up to 750 lbs. per sq. inch with a corresponding reduction in the weight and size to the horse-power developed.