Journal Institution of Locomotive Engineers
Volume 43 (1953)
|Steamindex home page
|Key file||The IMechE virtual library is accessible (full papers, all diagrams, photographs, extensive tables, etc).via the Sage system|
Den Hollander, F.Q. (Sir Seymour Biscoe Tritton Lecture).
Efficiency in the choice and application of locomotives. 12-28.
Special General Meeting held at the Institution of Mechanical Engineers, Westminster on 5 March 1953 at 17.30 at which The Sir Seymour Biscoe Tritton Lecture was delivered: President. C.M. Cock was in the Chair.
The Netherlands Railways. choice of motive power was based on the need for increased productivity and to reduce fuel costs. There was a high demand for passenger travel, and this was best met by electric multiple units which afforded high acceleration. On a few less intensive services diesel electric multiple units could provide the same degree of acceleration and afford comparable passenger comfort. On lines with very light traffic diesel railcars were used. Electrtic locomotives, which lacked the high rate of acceleration could be used on freight at night and on long distance pasenger services with few stops. It was considered that electric traction made the most effective use of fuel, most of which had to be imported into Holland.
Marsh, S.W. (Paper 518)
Recent developments in the use of rubber in railway engineering. 30-60. Disc.: 60-83.
General Meeting held at the Institution of Mechanical Engineers, London, on Wednesday 17 December 1952 at 5.30 p.m.: Mr. R.C. Bond, Vice-President, occupying the Chair who apologised on behalf of the President who was absent abroad,.
Author was Chief Engineer, Andre Rubber Company,
Showed the general made in the use of rubber in the Railway Industry in the last ten to fifteen years. It is confined solely to Locomotives, Carriages and Wagons and does not cover signalling and permanent way. It is not intended to include normal buffing and drawgear springs or auxiliary bearing springs, as such details have already been covered in past papers, and their use in the railway field is now well known.
1 . lntroduction.
2. The general advance which has been made in the compounding of rubbers, including use of the well-known synthetics, also bonding techniques.
3. General explanation regarding the design of rubber mechanical units, including some already in general use.
4. Units now under consideration and the trend in modern design work today.
Robertson, A.S. (Paper No. 519)
Limitations of acceleration and braking with electric traction: a study of the limitations imposed on performance by wheel to rail adhesion and electric traction equipment during acceleration and braking. 85-115. Disc.: 115-49.
General Meeting held at the Institution of Mechanical Engineers, London on Wednesday 14 January 1953 at 5.30 p.m., Mr. C.M. Cock, President, occupying the Chair.
Even on well maintained track, it is probable that small irregularities will initiate wheel slip, particularly when working at high speed and high tractive effort. Adhesion values up to and, above 20% can be obtained even at high speeds, but the probability of obtaining such a high figure at high speed is uncertain and depends to a large extent on the state of the track.
Journal No. 232
Bond, R.C. (Paper No. 520)
Organisation and control of locomotive repairs on British Railways. 175-216. Disc.: 217-65+5 folding plates. (incl. 2 col.). 6 iIlus., 4 diagrs., 11 tables.
Forty-second Annual General Meeting. held on 18 March 1953. President introduced Mr. R.C. Bond.
Main aim was to increase locomotive availability. Defined the classification of repairs into "heavy" and "light". Selection of locomotives for repair. Includes mileage/overhaul statistics for several classes as shown below.
AVERAGE MILEAGE BETWEEN PERIODICAL REPAIRS OF PRINCIPAL REGIONAL TYPES OF LOCOMOTIVES
|Region||Class of locomotive||Average mileage between periodical repairs|
|4-6-0 "Royal Scots" (taper boiler) and 5X conversions||
|4-6-0 Class 5||
|4-6-0 Class 5 with manganese steel liners||
|2-8-0 Class 8||
|2-6-4T Class 4||
|2-6-4T Class 4 with manganese steel liners||
|2-6-0 Class 4||
|2-6-0 Class 2||
|2-6-2T Class 2||
|Western||4-6-0 " King"||
|Southern||4-6-2 "Merchant Navy"||
|4-6-2 "West Country" and "Battle of Britain"||
|4-6-0 "Lord Nelson"||
|4-6-0 "King Arthur"||
A period in months since previous shop repairs was laid down for each class which, casualties excepted, had to elapse before locomotives were considered for shop repairs. This period was based on past experience, having regard to the nature of the service and the annual mileage the locomotives were running. Typical periods laid down for the then new BR standard locomotives were as follows:-
Class 7 4-6-2 15 months
Class 6 4-6-2 18 months
Class 5 4-6-0 24 months
Class 4 4-6-0 28 months
Class 4 2-6-0 30 months
Class 2 2-6-0 36 months
Class 4 2-6-4T 28 months
Class 3 2-6-2T 33 months
Class 2 2-6- 2T 36 months
Consideration was given to the different practices adopted by the
pre-nationalisation companies. Examination of locomotives coming in for overhaul
was considered to be very important. The limits of wear were considered.
The provision of spares was very important, especially boilers. Costing and
efficiency were significant.
Discussion: Opened by R.A. Riddles (pp. 217-18)Mr. R. A. Riddles, C.B.E. (Past-President) in opening the discussion, said he felt sure that all present would wish to congratulate Mr. Bond on a very valuable and informative Paper which would add greatly to the value of the Institution library, and to many private bookshelves. The system and method of the repair of locomotives on British Railways with which he had dealt in his Paper undoubtedly emphasised the care with which such work was undertaken, and it must be a considerable aid to the economy of the department as a whole. He was not surprised, but very gratified to find that Mr. Bond turned his back on his nursery and went to Crewe to find out how to do things! He only wished that Mr. Bond had included in his Paper his experience when he went to his secondary school at St. Rollox, where for many months, to his own knowledge, their belt was six days and not eight and from twelve pits in the erecting shops at St. Rollox no less than eleven engines, both heavy and intermediate repairs, were turned out every week.
The point of having as few engines as possible in the erecting shop was touched upon by Mr. Bond, but not empha ised other than the fact that at Crewe the erecting shop's capacity was controlled by the capacity of the machine shops to supply the bit and pieces to put back. The alternative was to give the machine shops so little to do that they were ready to grasp everything which came off an engine and to get it back on again before it had time to get cold! By those means at St. Rollox the schedule was so tight that in point of fact that was what actually happened. either the machine shop, the wheel shop, the copper shop, nor other auxiliary shops were ever working on something which was not required, and that was the secret of the belt which Mr. Bond had emphasised
A rather disturbing feature about the Paper was the statement that 85 per cent availability could be considered satisfactory. It would not seem to be satisfactory at all. It might be working towards the goal, but 5 per cent under or awaiting repair in the works was far higher by a considerable amount than it was on one particular railway for many months before the war. A desirable figure for the Author to aim at was in the region of 4 per cent although it had even been less than that figure. He recalled that his old chief used to examine the report on a Saturday morning, and if the figure were under 4 per cent, after 12 o'clock he would take Mr. Riddles across to the refreshment rooms and stand him a drink. If the figure were over 4 per cent Mr. Riddles had to stand his chief a drink! Fortunately, however, it did not cost him very much because at that time it was often possible to keep the figure down to as little as 3.5 per cent.
On the question of days out of service, Mr. Bond talked about eight-day belts. There were sixty engine pits and the Author referred to engines going through in eight days. It was true that one or two belts might be longer, but it would be interesting to know what happened to the other sixteen days in which the engines were awaiting or under repair. In the last report he saw he found that an average of twenty-four days were taken at Crewe, whereas in the Southern Region where belts had not yet been fully started, the same time was taken!
The total repair cost of £24 million certainly made one think, and as Mr. Bond' rightly pointed out, there was very great scope for efficiency, which to him meant the judicious spending of money, whereas to some, economy probably meant not spending it at all! By proper schedules and the proper attention to detail an attempt was being made at British Railways works to save money in that way. That gave greater efficiency and to that end perhaps the Author did not sufficiently emphasise the importance of initial examination. Not only was it necessary to examine a locomotive within a matter literally of hours of its coming into the erecting shop, it was essential to ensure that the work ordered to be done was only that actually necessitated by its physical condition. In short, a new pair of laces were not necessary each time one's shoes needed new soles.
In connection with Table IV it would be of interest to know what influence the new engines had on the exceptionally high mileage of the Class 2 engine. It seemed extraordinary that the Class 2 engine should have such a high mileage, and perhaps it was a quantity of new engines which had made that high mileage average possible. He desired to draw attention to the statement under "Locomotive Availability" to the effect that the reasons for locomotives not being available for traffic came under certain heads, the two main items of which were at works for repairs and waiting works repairs. In his view that was not correct, and the third item, namely engines waiting for material, was more important than either. Not only was he grateful to the Author for his excellent Paper, but he desired to say how much he appreciated the efforts of those engaged in this very important work, because without their personal interest, nothing like the story which Mr. Bond had told would have been possible.
Sir William Stanier, F.R.S. (Past-President) referring to himself as one of the "has beens," said that it was a long time since he left the locomotive works, but he had been very interested in Mr. Bond's Paper. The Institution had once more gained that which would be a book of reference in a great many quarters. In the past the Institution had been fortunate in having outstanding papers, and now there was another Paper which would be read with interest all over the world. There were one or two items which puzzled him, but it might perhaps be due to the fact that he had been out of touch for so long. For instance, there was the mileage of the various locomotives set out in Table IV. When he had something to do with locomotives on the LMS it was considered very important to maintain the efficiency of the locomotives, and there was a scheme by which engines were called in for intermediate repair at about 60,000 to 70,000 miles, and given general repair at about 110,000 to 130,000 miles. The mileage shown for the various engines in the table was much lower than he would have anticipated unless, of course, they were taken on intermediate repairs and it was done in order to maintain a good standard.
When discussing the belt system, the Author stated that the system could be introduced in erecting shops with cross pits and it would be interesting to know whether that had in fact been done. He appreciated that it was possible if the cranes were sufficiently high to lift engines over one another, but he would like to know whether it had been done. He desired to pay tribute to the Crewe erecting shop and to the organisatior: connected with i~. The shop was built in 1924 largely at the instigation of the late Major H. P. M. Beames, one of whose nght hand men and the one who was responsible for organising the planning, was Mr. Riddles. He was now reaping the benefit of his early work. He desired to thank Mr. Bond for placing before the Institution such a complete report on the maintenance of locomotives.
K.J. Cook (219-20) (Vice-President) said that the paper was rather a long one and contained a good deal of descriptive matter. It was, therefore, a little difficult to pick out many points upon which to speak. He did desire, however, to quote the Author's statement in referring to the basis of selection for repairs, that" The wide variations in mileage at which individual locomotives of the same class require attention in the works, to which reference has already been made, clearly preclude the use of average mileage between repairs as a satis- factory basis for determining when the locomotive should be sent to the works." That, Mr. Cook, suggested, was an illogical statement. Provided there were the fundamentals of accuracy of repair and close tolerances, for which basis accuracy was necessary, then the mileage basis should become and was the only really logical basis on which to make the preliminary selection.
He was rather perturbed to see that so many engines of certain main line classes required general or intermediate repair at considerably less than 40,000 miles. He suggested it was due to the fact that there was fundamental inaccuracy. If the basis particulars of the locomotive were dealt with with real precision, then if the engine fell down before it ran to within a very close distance of the specified mileage figure there was obviously some definite cause. From his own experience he could say that where engines were repaired with basis accuracy and close tolerances, it had been extraordinary how closely they ran time and time again and right throughout the classes to their average mileage. In his view there were at least four reasons, three of which were quoted in the Paper, that could be put forward to suggest that mileage was really the correct guiding basis for repairs. h. Bond had referred to the measure of making good wear and tear, and that measure was the mileage run; unit cost was expressed as cost per mile, and it is also stated that the costs of maintenance and mileage between repairs were related to design features as a guide to future policy and practice. He suggested that that was the simplest method in which to make the selection and the very first question, with- out exception, which was asked by the Shopping Control was: -what was the mileage since the last repair? If engines were accurately repaired he suggested that the mileage was the best and simplest method wbich could be used.
With regard to the graph in Fig. 2, it would seem that the actual description of the number of repairs required needed some modification in that repairs under that definition included new engines. At the present time when stock was virtually stationary, mileage was made good by repairing or building and condemning.
Under "Provision of Spares" the Author stated: "At one works" he was probably referring to Crewe "where the trouble was particularly acute, the problem was met by building one spare set of frames complete with cylinders, dragbox and stretchers for each of three numerically large classes of locomotive, with outstanding benefit to the progress of repairs at a time during the late war when every locomotive was needed for traffic." According to English parlance he did not think that that was" playing cricket," as it affected days under repair and it did not appear that the argument that it had, been sound financial policy to provide spares to that extent held good!
J.F. Harrison (220) mainly noted that the primary loss in time was through shortage of materials in the erecting shop.
R.A. Smeddle (220-1) commented on statement (page 181) that the frequency of repairs was governed as much by the mechanical condition of the locomotive as by the boiler. To some extent it depended, in his view, on which region of British Railways was being discussed. In some regions it was found that boilers lasted longer between repairs than in others. If one was fortunate to obtain a large mileage out of the boilers, it was almost invariably found that there was trouble with worn tyres, loose axle boxes, etc., although the latter had to a great extent been cured by the by the fitting of manganese-steel liners to the boxes. That was proved on reference to Table IV where a great improvement is shown on Class 4 and 5 engines as a result of the use of manganese-steel liners. If the boiler would hold out, as apparently it did on regions with water softening, then it was a great help to securing greater mileage between repairs. On the subject of mileage, he was interested in Table III where the average mileage from general repair was said to be 64,268 miles. Surely that was rather low. He extracted the Western Region's figures and found that the mileage was 80,000 and average time in months from general repair 41. It therefore appeared that the mileage was slightly lower on some of the other regions. The higher average on the Western Region might be accounted for by the attempt being made to put the best into the repair of the engines. He had worked on three regions, but was not so familiar with the LMS, or Crewe, and in his view the quality of the repairs at Swindon had a great influence on the mileage which it was possible to obtain there between general repairs and between general and intermediate repairs, the mileage between the two being approximately the same. The statement on page 188 that the smaller the number of days taken to repair each locomotive, the lower will be the number of engines at the works was interesting. The aim was, therefore, to complete the repairs in the shortest possible time. He suggested that it might be better to put it round the other way and reduce the number of engines in the erecting shops. That was done at a works with which he was previously associated. Weeks were being taken to repair the engines so a number were taken out of the shop and the reduction in the number of days as a result was surprising. With regard to the staging or belt at Crewe, at Swindon there was similar staging of repairs. The pits are arranged transversely with a traverser in the middle and engines were moved to the various positions by means of overhead cranes.
R. Arbuthnott (221-3) from the private locomotive manufacturing industry commented on the huge improvement wrought by the use of manganese steel axlebox liners, and asked why they had not become universal, and also asked what improved boiler boiler and was informed by Bond (230): better water quality, higher standard of shed maintaenance, and improvements in design: ample water spaces, larfe radii in the bends of firebox plates and steel or monel firebox stays.
E.S. Cox (223-5) added very little apart from noting that the use of manganese steel axlebox liners had increased tyre life and that some modern designs were excessively complex (he was presumably refering to multiple cylinders).
H.H. Swift (225) noted that a system of progressive repair had been introduced at Ashford and that this had led to a 10% improvement in productivity.
I.C. Forsyth (225-8 (3 illus.) described a welding repair method adopted at Crewe for fitting a pre-assembled front-end onto the Princess Royal main frames, which indicated that trouble was experienced through the cylinders working loose and fracturing..
Meeting at Doncaster on 19 April 1953; J.G. Dickson in Chair
R. Hart-Davies (240-1) said that it was with some trepidation that he spoke on this occasion because, he had the responsibility of being Chairman of a Committee dealing with Locomotive Maintenance Standards, and that when he saw the size of the task ahead as revealed by the Paper he realised it would take a long time to accomplish. He was puzzled by the figures in Table I in which the mileage obtained between general repairs is shown as averaging 101,000 for all engines compared wIth the mileage from general to intermediate repairs of some 64,000.. He was always under the impression that by the time the boiler received a general repair the engine had completed two penods in service and that at the halfway mark, which was the intermediate repair, the mechanical parts were restored to a state in which they would run practically an equal amount of mileage before again requmng repairs. He felt that when average figures are taken results an be misleading and that a more realistic comparison is obtained from figures for each class of engine separately. He thought that on the question of mileage between shop repairs it was important that the initial play and tolerance allowed in moving parts and bearings of all kinds .should be made as small as possible consistent with proper operatIon to start wIth. Thus the time taken and miles run before that degree of " knock " develops which necessitates bringing the 'engine into the works, would. probably be much greater. He thought this was one of the most Important considerations in connection with maintenance. The Author mentioned that the statistics used in his Paper were on a 6-day basis, whereas our present working week is one of 5 days. He asked if there is any likelihood of a change in the form of statistics to bnng them to a 5-day basis in the future.
Dymond, A.W.J. (Paper No. 521)
Operating experience with two gas turbine locomotives. 268-336.
Sixth Ordinary General Meeting of the Session 1952-53 held at the Institution of Mechanical Engineers on Wednesday 18 February 1953 at 17.30;. C.M. Cock, President, occupying the Chair.
Brown-Boveri gas turbine locomotive No. 18000 and Metropolitan Vickers locomotive No. 18100. Discussion: Sir William Stanier (pp. 292-3) made pertinent remarks on the gas turbine locomotives, and the difficulties encountered with operating the steam turbine locomotive on the LMS (reproduced in section on Stanier)
E.F. Spanner (305-6) wrote that a train heating boiler built into and forming part of a powerful modern locomotive can be a tremendous nuisance if it fails to function properly, and robs the train of its heating service. Writing as one personally responsible for a number of train heating boiler installations he observed that:train heating boilers require: adequate space, a reasonable allocation of weight, a compartment well ventilated when moving in either direction and an adequate and non-aerated feed water supply. Too often the space offered is unduly limited and a good job cramped for as little as an additional 6 in. on length and 6 in. on width of floor space. Two principal types of train heating boiler equipment are available: flash type and lightweight firetube type. There is a fundamental difference between the two in regard to character . and weight, type first being light in weight but heavy on maintenance and second being from 25% to 50% heavier, but of robust and long lived construction. When account is taken of the weight of fuel and feed water which has to be carried for a normal run, the difference in weight between type (1) and (2) is reduced to less than 10%. (c) An oil-fired train heating boiler requires a great deal of air at from 1 to 2 in. w.g. pressure for maintaining combustion under all conditions, i.e. with the locomotive at speed in either direction, in the open air and through tunnels, cuttings and so on. Cases have occurred where excellent results were secured running" ahead," as as it were, and poor results running" astern." There have also been cases in which the combination of a restricted compartment, a boiler of high output and little ventilation has resulted in the operation of automatic controls being affected. . (d) Feed supply to an oil-fired boiler is seriously affected by conditions at the suction end of the feed line. Special precautions should be taken to ensure;(1) that the suction is always well drowned at all times and under all conditions of acceleration and deceleration, running around right and left hand curves and so on; (2) that where possible, arrangements are made to ensure that the water tanks are filled with inert flue gas rather than air (this involves taking gas from the boiler flue to the air inlet and air escape to the feed tank); (3) that good water is used and~the boiler washed out periodically; ( 4) that the boiler, is filled right up to the crown from the non-aerated feed tank at each" shut down," in order to prevent air being "pulled back" into the boiler so causing corrosion above the water level. Attention to all these points, and to the selection and maintenance of adequate controls is essential to the establishment of satisfactory running service.
G.W. Carpenter (332) wrote that in the Paper the performance of the Brown-Boveri 2,500 h.p. locomotive is compared with that of a King Class 4-cylinder 4-6-0. The locomotive working details given with the speed distance curves for the Cowley Bridge Junction-Whiteball and Athelney-Somerton Tunnel sections indicate that the mean power output of the gas turbine machme was about 90 per cent of its rated maximum in the first instance and that full power output was used for the bulk of the second section.
The comparative performance of the King Class locomotive quoted in the Paper is, however, very moderate in relation to maximum recorded performance. by these locomotive; in ordinary service. Such runs have. included. times of 20¾ minutes from Cowley Bridge Junction to Whiteball with 417 tons tare and 23 minutes with 537 tons tare, whilst a Castle Class locomotive covered the section in 21½ minutes with 460 tons. The performance of the Brown-Boveri locomotive between Athelney and Somerton Tunnel has been equalled by a King hauling a practically identical load (381 tons tare) whilst the comparative King performance quoted has been equalled in ordinary service with 537 tons tare, a tonnage heavier by nearly 50 per cent.
It is, therefore, reasonable to assume that the performance of the e King Class locomotive quoted in the Paper was achieved at an appreciably lower percentage of the maximum power output which these locomotives can sustain than that of the Brown-Boveri locomotive. The Paper also states that the sustained high rate of drawbar horsepower developed by the Brown-Boveri locomotive. Is beyond that normally possible with the maximum continuous capacity of any steam locomotive in the country. . From published data the Brown-Boveri locomotive appears to be capable of developing about 2100 h.p. at the wheel treads at full power output at speeds between 40 and 8O. m.p.h. Corresponding drawbar horsepowers, with locomotive frictional and air resistance calculated on the basis of other locomotives of similar weight and wheel arrangement, may be estimated at 1700 at 80 m.p.h., 1900 at 60 m.p.h. and 2000 at 40 m.p.h.
Sustained power outputs developed at speed by British express passenger locomotives recorded by competent observers, using train and locomotive resistance formula which have been proved to give a reasonable degree of accuracy, indicate that the 4-6-2 type locomotives of the former L.M.S., L.N.E. and Southern Railways are capable of sustaining maximum drawbar horsepowers equal or superior to those of the Brown-Boveri locomotive, whilst the Kmg Class 4-6-0 locomotives, despite their relatively smaller grate area, can sustain maximum drawbar horsepowers closely approachmg those of the gas turbine locomotive. The appreciable penods of time during which these power outputs were sustamed. would appear to indicate that the boiler capacity of the locomotive concerned is adequate to sustain such efforts for lengthy periods, limited only by hand firing. This limitation could, of course, be overcome by the provision of mechanical stokers, if it is desired to sustain such power outputs for very lengthy penods.·
Published data for the Metropolitan-Vickers 3,000 h.p. locomotive shows this machine to be capable of developing 2,400-2,500 h.p. at the wheel treads at full power output, at speeds between 40 and 80 m.p.h. Corresponding drawbar horsepowers may be estimated at 2,000 at 80 rn.p.h., 2,300 at 60 m.p.h. and 2,400 at 40 m.p.h. Whilst these values of drawbar horsepower are superior, at speeds of 60 m.p.h and under, to the maximum sustained outputs normally obtainable with existing British express passenger locomotives, it is doubtful If existmg British traffic conditions enable such power outputs to be sustained for any length of time, except with heavy trains on severe gradients. Should traffic requirements demand the development of sustained power out-puts of this order, it is doubtful whether 4-6-2 type locomotives would have adequate adhesive weight to sustain such power outputs in bad rail conditions. It may, however, be mentioned that the 4-cylinder compound 4-8-0 type locomotives of the French National Railways have frequently sustained power outputs of 2,500-3,000 d.b.h.p. over 1engthy periods at speeds between 40 and 80 m.p.h. even in bad rail conditions. These locomotives weigh 105 tons m working order, without tender. A simple expansion locomotive of this type with equivalent boiler capacity should, therefore, be capable of sustaining 2,250- 2,700 d.b.h.p in this speed range, even in adverse weather and rail conditions, and would appear to merit consideration if locomotives of enhanced traffic capacity are required.
Journal No. 233
Reed, Brian (Paper No. 522)
Running tests of a 500 h.p. diesel-mechanical locomotive.. 366-97. Disc.: 397-411.
Ninth Ordinary General Meeting held at the Institution of Mechanical Engineers, London, on Wednesday 15 April 1953, at 5.30 p.m., Mr. C. M. Cock, President, occupying the Chair.
The losomotive tested was one of two eight-wheel 500 bhp machines built for Peruvian Corporation for service on the Paita-Piura Railway, a 62-mile line with short grades of 1 in 29-30 and longer grades of 1 in 35-50, laid almost entirely without ballast. The specified top speed was 33 m.p.h.; and most of the freight traffic and the few mixed and passenger trains on this route were handled by these two 55-ton locomotives, which had been in revenue service now for a year with satisfaction.
J.F. Alcock (400) remarked that the locomotive in question was one which he was inclined to look upon as his own locomotive so that his personal pleasure could well be imagined when Mr. Riddles agreed to accept it for test on British Railways and especially when the dynamometer car was made available. He had also been highly delighted when such an authority as the Author offered to take personal charge of the trials; in fact, the Author took such personal charge of them that whenever Mr. Alcock happened to go on one of the runs in order to discuss the matter with Mr. Reed, any such discussion proved quite impossible because the Author was checking times against mile-posts with a stop watch in one hand and a pencil and notebook in the other. There is no doubt that the Author had done an extremely good job in running the trials and had presented a most interesting Paper. It should also be mentioned that the consulting engineers, Messrs Livesey & Henderson and, of course, the customers, The Peruvian Corporation, had been extremely helpful and co-operative in allowing the delivery of the locomotive to be delayed while the trials had been carried out.
He would like to make a few comments on special points which he had noted in going through the Paper. Figure 3, for instance, did not clearly show that all the bearings were fully self-aligning. All the shafting between the engine and the gearbox was, in fact, fully articulated in the sense that any movement in the frames could not produce any stress on any of the details, an important point which in years gone by, had caused a great deal of trouble and particularly crankshaft trouble.
On the following page, reference was made to the drivers. There had certainly been a good deal of trouble due to union restrictions. It was stated in the Paper that eventually there were four drivers, but Mr. Alcock thought that there had been many more because each time he had gone to the locomotive, there appeared to be a different driver in charge. When one enquired about it, one was told that it was because the driver who had been on for two days, had a day off, and the man who would be on next week, had come on the day before, while the man who was on the previous week, had been on the day after and so on. There was, however, consolation in the fact that the locomotive was certainly having a good testing.
On page 373, reference was made to the fitting of an excess fuel stop gear and he would like to explain the detail. All diesel engines, of course, had excess fuel stops. It was not really a question of fitting an excess fuel stop, but of modifying the fuel stop. There had originally been thc usual device which allowed a small amount of extra fuel for starting up from cold and this had been controlled by a pull wire from the cab. It was, however, discovered as, looking back, one ought to have appreciated, that if anybody wanted extra power it was only necessary to pull the wire to obtain it; that had certainly not been the purpose of the gear and, therefore, modifications were carried out and the gear redesigned so that this could not occur.
With regard to engine rating, it must be remembered that the locomotives had been in Peru for a year, and the tests which had been described had been conducted in 1951. Two years had been taken up in building the locomotives prior to that and the inception of the idea went back probably another 12 months or 2 years, so that the rating had probably been agreed upon 5 to 6 years ago. He remembered discussing it with the late Mr. Ted Paxman. At that time the engine had been designed to carry 660 h.p. at 1,500 r.p.m., that was, the onehour overload rating. They decided to derate about 25 per cent, 10 per cent being taken oft the speed, bringing it down to 1,375 r.p.m. and 15 per cent off the fuel loading which gave a figure of 500 h.p. at 1,375 r.p.m. Mr. Alcock regarded it as a very suitable rating for the cngine in every way. As will be seen from some of the curves, the torque of the engine began to fall away at about 1,050 r.p.m. at which speed peak torque was obtained. As is usual on a diesel engine when it begins to stall down from maximum speed, torque increases until peak torque is reached. This gives an excellent self-compensating effect and it can be seen frequently on the dynamometer curves that the engine can hold on somewhere about 1,100 to 1,200 r.p.m. and it is only when the duty becomes too onerous and the engine stalls below the peak torque position at 1,050 r.p.m., that a gear change down has to be carried out.
On page 381, the question of wheel slip was raised, a very interesting point. As the Author said, there was hardly ever any real slip which amounted to anything. That was quite understandable. When a wheel slips, there is an immediate reduction in torque; as a consequence the engine speeds up and the automatic governor then immediately shuts down the fuel, consequently the wheel slip is checked almost instantaneously while the driver, with a somewhat slower reaction than the engine governor, checks back on his throttle control and so gains control again within less than a second. He then picks up the throttle again until the engine is on load and, as shown by the dynamometer charts, the slip is hardly measurable in time, while the tractive effort has only been reduced by about 30 per cent. In practice, the effect really was amazing. The same type of thing occurred exactly whether the friction clutch was fitted or the hydraulic coupling. He hoped shortly to make a similar test with a hydraulic torque convertor, but he did not think that quite the same result would be obtained, although it certainly should be a great deal better than the result obtained with. a steam locomotive. The problem, of course, on a steam locomotive is that however quickly the driver might bring back his regulator, there was always a considerable amount of steam in the steam pipe and steam chest which had to get away through the cylinders before the driver could take control again.
Reference to a steam locomotive slipping brought his mind back to an incident which occurred some months before the diesel locomotive went on trial. He decided to make a trial run over the same track on which the tests were to be carried out. A steam locomotive was, of course, on the job. He chose, as it happened, the worst possible morning-foggy and wet with autumn leaves on the track and it certainly had been an experience, in fact, to anyone except a railway man, a terrifying experience. Slipping and severe slipping was occurring every few moments and the driver had his work cut out to control it. The train, on several occasions, almost came to a standstill and there was danger of it running backwards down grade. The fireman certainly had all his work cut out looking after his own job. There were, of course, several tunnels, one of them only 100 yards long, but it can be imagined that it seemed very much longer when slipping. Slipping in a tunnel for any length of time is not a pleasant experience and it really was remarkable to see the ease and simplicity with which the diesel locomotive carried out much more onerous work at a later date. Mr. Sinclair, in his remarks, had made it obvious
Discussion: O.S.M. Raw (405) asked whether the gearbox was running in Peru in the appallingly noisy state which had been mentioned, or whether it had been silenced; also what was the cost of the locomotive the tests of which were described in the paper. It was admittedly, he added, a completely prototype locomotive, so that cost might not afford a fair basis for judgment, but it would be interesting to have an idea of what an electric transmission locomotive of the same horse-power would cost compared with the one in question, based on the same numbers for production and communicated that Cantlie had very wisely commented on the fact that the troubles with the fluid coupling should not be stressed. They are normally most reliable and trouble free as the writer found from experience having maintained a large number of them which were fitted to large diesel engines used on oil well drilling rigs. He felt that there must have been some maladjustment in the one on the locomotive under trial and he expressed surprise that the matter was not referred to the makers at the time, or before, the locomotives yere shipped to Peru. It would appear that they were not properly adjusted before shipment as he had heard that on one locomotive it has been removed. Having been at the receiving end abroad the writer strongly urged that nothing should be shipped out unless it is proved to be absolutely right.
With regard to the gearbox noise we are informed that this has been somewhat improved. The real point is not to have excessive sound which has to be damped. The writer suggested that if it is not a case of insufficiently stiff shafts or bearings inside the box that the noise is greatly amplified by the shape of the box which is a simple rectangle in shape with a flat lid, a shape which seems to have been specially designed to augment any noise which it may produce.
It is essential that they must be properly clipped up and supported. In addition the trouble can be caused if these pipes are not properly annealed when they are made, and they must be re-annealed at regular intervals. Also, trouble can be occasioned by constant polishing and this might well occur overseas and in Peru where labour to maintain locomotives properly is still available. In the Army in the last war it had to be forbidden by order to polish copper fuel and other pipes. Ex-cavalry regiments full of zeal for "spit and polish " kept these pipes on the armoured vehicles and lorries beautifully polished, yet this was the cause of many deaths in the desert due to the constant polishing Mention has been made of trouble from fractured oil pipes. causing the pipes to fracture on service so allowing the crews to be stranded. Orders forbidding the polishing of copper pipes and that they should be regularly annealed are essential. A still better improvement would be to make such pipes out of solid drawn steel. It has been stressed that trouble has not been experienced with the main components, but only with the auxiliaries. This is the case with all locomotives, but in a steam locomotive the failure of an auxiliary is not so vital, whereas on a diesel locomotive it usually results in the complete failure of the locomotive.
In conclusion the writer enquired why a rigid 8-wheeled design was chosen for a sinuous line. The previous steam locomotives were eight-couplcd, but the writer fet sure that they had leading pony trucks.
Morgan, R.E. (Paper No.523)
The development of the Farnboro electric indicator and its application to the steam locomotive. 412-21. Disc.: 421-5. 6 diagrs.
Fourth Ordinary General Meeting of the Manchester Centre held at Reynolds Hall on Thursday 26 February 1953 at 6.30 p.m., the chair being taken by Mr. D. Patrick.
Also reviews locomotive indicator development in general including mechanical Indicators, e.g. Dobbie McInnes and Maihak. These indicators are simple in design and use and lend themselves to easy calibration under static conditions. They require some form of reducing mechanism, usually in the form of a linkage system driven from the crosshead, since in most cases the size of the diagram is only of the order of 3 in. x 1½ in. The pressure measuring element has appreciable inertia and this can easily lead to spurious effects, especially at the higher engine speeds. They are usually used for stroke base diagrams, but are adaptable.
Optical Indicators-Cathode Ray type, e.g. Cossor, Dodds. These indicators then required "complicated electronic systems" and produced small diagrams. The inertia effects are negligible and they can be used on either crank angle or stroke base. In most cases the pressure measuring element is sensible to changes in temperature and this must be compensated for. This type of indicator is very suitable for extremely high engine speeds and is chiefly used for comparative analysis of cylinder events. A high speed cine camera was often employed when these indicators were in use. Both mechanical and optical indicators give an indicator diagram for each cycle of events.
The Famboro Electric indicator was simple in design and easy to operate. It is designed to be driven from the axle or crank shaft of the engine and the diagrams, 14 in. x 7 in., are usually taken on a time base. The inertia of the pressure measuring system is negligible even at high engine speeds and the indicator is quite simple to calibrate.
These indicators give diagrams on either a stroke base or a time base or both. The stroke base diagram has the major advantage of permitting the easy computation of i.h.p., but this is really the only thing to be said in its favour. On the debit side are : the size of the drum, and therefore the diagram, must be small to reduce inertia effects due to rapid acceleration at high speeds. Secondly, the diagram is cramped at the ends where the principal valve events occur, that is, lead, cut-off, release, depending of course on speed, and a 3 in. diagram does not lend itself to accurate analysis from this point of view, if the effects of deliberate changes in valve events are to be analysed.
With the introduction of large scale testing of locomotives by British Railways after WW2, the problem of the most suitable type of indicator for use on a steam locomotive had to be decided. Spring and piston indicators of the Crosby type had been generally employed for indicating trials on the road, and experiments with cathode ray type indicators had been carried out prior to the war both by the LNER and LMS, but the results were inconclusive. The decision reached was that the Farnboro indicator appeared to be the most suitable and after consultation with Messrs. Dobbie McInnes, manufacturers of this type of indicator, two of these machines were ordered, one to be used at Rugby Locomotive Testing Station, the other by the MTUs for trials on the line.
It must be stated here that the Farnboro indicator was not originally designed for use on a steam engine, but was principally intended for the indicating of piston type aero engines, both on the test bed and in flight, but it was hoped that the special type of pressure element supplied for use on a locomotive would overcome possible difficulties caused by condensation occurring on the insulating material used in the element.
The Farnboro system consists essentially of a pressure measuring device and a machine on which to record that pressure at its appropriate piston position The pressure measuring device, known as the element is located in the cylinder cover of the engine being indicated. The element has a shuttle piston which is subject on one side to cylinder steam pressure and on the other to a reference air pressure which can be varied as required by means of a control cock on the indicator. This piston, whose movement is restricted by electrical contacts, is free to move under the influence of either air or steam pressure depending on which is the greater of the two.
Discussion: J. Fore (p. 422) asked how the system was adapted for four-cylinder locomotives and was informed that in the case of a four-cylinder engine (8 beats per revolution) the dead centres and therefore the diagrams would be spaced at approximately 45 of crank angle. When the locomotive had only 4 beats per revolution then there would be no alternative but to take two separate cards, and accept the time interval between them, care being taken to ensure that the boiler pressure and speed remained the same for each card.
D. Patrick (p. 421) had opened the discussion and received the following response: the matter of all cylinders being indicated simultaneously was a most important point in favour of the Farnboro indicator. The diagram for each cylinder end was formed as had been described earlier, but four or more elements could be used, each element recording by means of the spark which punctured the paper the exact point at which the reference air pressure was balanced by the cylinder steam pressure and its appropriate phase position. Considering one revolution, each element gave two sparks, then for a two-cylinder locomotive eight sparks per revolution would be recorded, all on the same pressure ordinate, but correctly spaced in accordance with the angle between cranks, and the cut-off of the locomotive concerned.
Journal No. 234
Bond, Roland C. (Presidential Address)
Years of transition. 439-63 + 4 folding plates. 15 illus., 7 diagrs.
This address surveys the post 1923 period in broad economic/technological terms. It reflects the policies of Bond's former chief (Stanier). Bond examined six experimental locomotives:
1. Armstrong-Ramsay Condensing Turbine Locomotive.
2. Beyer-Ljungstrom Condensing Turbine Locomotive.
3. Schmidt-Henschel High Pressure. LMSR 4-6-0 6399.
4. High pressure compound with water tube boiler. LNER 4-6-4..
5. Non-condensing Turbine Locomotive. LMSR 4-6-2. 6202.
6. Simple expansion 0-6-6-0 "Leader" Class. Southern Rly:
Of these locomotives the most successful was, I think, the LMSR condensing turbine locomotive No. 6202. It ran 439,931 miles in earning service; and although fuel economy was limited to that which could result from a reduction in heat losses compared with a reciprocating engine working between the same temperature and limits, dynamometer car tests showed a saving in coal consumption of approximately 7 per cent. Certain mechanical troubles were experienced and the availability record of the locomotive was not As a result of the experience gained over a period of 15 years, decided to convert this locomotive to 4-cylinder simple propulsion..
The LNER high pressure compound locomotive did not come up to expectations. It was fitted with a water tube boiler in which the hot gasses were drawn horizontally from the firebox by way of a series of baffles through the forward banks of water tubes. It was soon apparent that the circulation was unsatisfactory and, in view of the steaming difficulties expeiienced, a full size model of the front portion of the boiler was constructed and experiments carried out which revealed that short circuiting of the gases was taking place. Considerable modifications were made to the arrangement of the baffles in an endeavour to bring the products of combustion into contact with the whole of the forward banks of water tubes. As originally built, the locomotive had two high pressure cylinders 12 in x 26 in. and two low pressure cylinders 20 in. x 26 in. but, as a result of the steaming difficulties, the high pressure cylinders were subsequently reduced to 10 in. in diameter. In spite of the modifications to the boiler and the reduction in the diameter of the high pressure cylinders steaming was only satisfactory when the locomotive was developing high power at long cut-offs, with a smokebox vacuum in the region of 6 in., and under these conditions the smokebox temperature was too high. Some slight improvement was effected by fitting twin blast pipes, but notwithstanding the various alterations carried out this locomotive did not prove economical and, in general, it burnt considerably more coal than the standard Pacifics. It was therefore rebuilt as a 3-cylinder simple with a boiler of standard design working at 250 lb./sq. inch.
Nor was the Schmidt-Henschel LMSR 4-6-0 Fury successful. Repeated tests and many modifications were made over a period of two years in attempts to make the boiler steam. Combustion was not good, steaming was always most unreliable and coal and water consumption excessive. Fury was never able to take its place in normal service. One serious tube explosion occurred and the locomotive was rebuilt and appeared as No. 6170 British Legion, becoming the prototype for the converted Royal Scots, one of the most successful 4-6-0s ever to run in this country.
Neither of the two condensing turbine locomotives fulfilled expectations under the traffic conditions of the Railway on which each was respectively tested. The Ramsay locomotive was designed to give a performance approximately equal to the LNWR Claughton Class express passenger locomotives. It was found on arrival at Horwich for tests, to be considerably above the designed weight and its route availability was thus severely limited. The results of trial runs were most unsatisfactory. The forced draught system did not allow proper combustion to take place and the boiler pressure could not be maintained, even when running light. The inability to steam was also due to the fact that the condenser, instead of producing a vacuum of 27½ in. for which the turbine was designed, was frequently unable to reach 20 in. Many modifications were made and further trials conducted, but the performance both of the boiler and condenser was still inadequate. When the vacuum fell slightly the demand for steam increased rapidly and could not be met; the pressure fell and the turbine, being unsuitable for a lower pressure, could not take the load. Coal consumption was very high in relation to work done.
The Beyer-Ljungstrom locomotive was tested over a period of eighteen months on passenger and freight trains on the Midland main line, including St. Pancras-Manchester express passenger trains. Good time was usually maintained with trains of normal loads and while the boiler steamed well, condenser vacuum varied rather widely and was particularly susceptible to the effects of running through tunnels. Coal consumption was, in general, no less than with normal locomotives engaged on similar duties.
The most recent example of the unconventional was the Southern Railway Leader Class in which two 3-cylinder totally enclosed sleeve valve engines were mounted on six-wheel bogies with all weight available for adhesion. The boiler, off-set from the longitudinal centre line of the frames, was of all-welded construction, the firebox heating surface consisting essentially of thermic syphons enclosed by solid firebrick walls. Since the high availability and reduction in maintenance costs and fuel consumption which were aimed at, are just those things for which we are continually striving, .the utmost pains were taken in attempting to overcome initial troubles and to give this unusual design every opportunity to prove its worth. A number of modifications were made and many trial runs were undertaken, but the locomotive could not be made capable of sustained work or reliable performance. The principal causes of trouble were breakages of valve gear parts, fracture of the crank axles and difficulties with the brick walls of the firebox. The engine weight was excessive and its distribution faulty, the firing cab was excessively hot and most carefully conducted dynamometer tests showed there to be no improvement in thermal efficiency. The disappointing results which have attended the effork to break away from normal lines of development in this country are typical of ,experience generally.
|Eastern Region A1 (then almost new)||93,363|
|Western Region Castle||87,424|
|Eastern Region A4||86,614|
|Southern Region Lord Nelson||81,611|
|Western Region King||78,987|
|Southern Region Merchant Navy||75,687|
|Southern Region West Country||74,650|
|London Midland Region Duchess||73,188|
|London Midland Region Rebuilt Royal Scot||70,495|
|London Midland Region Class 5 4-6-0||56,969|
The largest single source of further economy in steam traction costs is in reduction of expenditure on maintenance in shops and sheds. Although the average mileage between repairs in works has increased by nearly 30 per cent during the last thirty years, there is considerable scope for further improvement. The average mileage between consecutive general and intermediate repairs for all steam locomotives is approximately 65,000 at present. But many of the most modern types, both large and small are proving themselves capable of running more than 100,000 miles before requiring heavy repairs in the shops. This result has been attained by a constant process of elimination of weaknesses in design, material and maintenance methods. More can yet be done by extending chemical treatment to improve the quality of boiler feed water supplies. As the proportion of new locomotives embodying those features of advanced mechanical design which have been found to contribute most to higher mileage between repairs increases, and others with some years of service ahead of them are modified in the same way, there is no reason why the average mileage between repairs should not be substantially increased without any loss of operating efficiency. Finality has not by any means yet been reached, and the target at which we must aim is an average mileage of at least 100,000 miles between consecutive repairs in shops. Better axle bearings, harder tyres and rotary valve gears may assist still further in this respect and, as I pointed out in a Paper on (' Locomotive Maintenance " which I recently read to you, the stimulating effects arising from the critical examination to which every phase of the maintenance organisation has been subjected during the last five years will be felt to an increasing extent in the future, and will apply alike to all forms of traction.
Micklethwaite, N. (Paper No. 524)
Distribution of fuel on British Railways with regard to coal and coke. 464-73. Disc.: 474-5.
Fifth Ordinary General Meeting of the North Eastern Centre held at the Danum Hotel, Doncaster, on 29 January 1953 at 7 p.m., the Chair being taken by Mr. D.C. Stuart.
Next to wages fuel was by far the greatest expense in the motive power department. In 1951 coal and all fuels, the vast majority being coal, cost £38 million as against an overall wage bill in the motive power department of £45 million. The coal consumed was 13,549,000 tons in all regions, the Eastern and North Eastern Regions using 2,600,000 and 1,097,000 tons respectively. These figures were not decreasing and it was therefore our main aim to keep these costs as low as possible
Compton, J.N. (Paper No. 525)
The design and construction of steel fireboxes. 475-96.
Third Ordinary General Meeting of the North Eastern Centre held at Great Northern Hotel, Leeds on 10 December 1953 at 6.45 p.m., the Chair being taken by Mr. J.G. Dickson.
The author probably worked for the Yorkshire Engine Company. Advantages of copper fireboxes:
(i) Superior conductivity with the result that the rate of heat transfer is higher than with steel, in spite of the necessity for using a thicker section.
(ii) Long life: even with water of low alkalinity corrosion is negligible.
(iii) Easy material to work under manufacture and comparatively easy when repairs by patching are required provided particular skilled labour is available.
The disadvantages, and therefore the advantages of steel fireboxes more than outweigh the advantages:
1 . High cost even after setting off higher scrap value.
2. Necessity for riveted construction. Although copper fireboxes have been constructed by welding, both in Britain and on the continent, it cannot be said that it is accepted practice, and copper fireboxes continue to be built by the riveting method. The disadvantages of riveted lap joints are cost of manufactures, the skill required involving what must be looked upon as a declining trade and the localised overheating and concentrated stress resulting in the development of cracks particularly in the region of the caulked seams.
3. The adoption of steel for fireboxes presents a comparatively simple fabrication which can be built up by arc welding of butt jointing seams with comparatively thin plate. Evcn the tube plate need be no thicker than ½ in. for normal steam pressures instead of the specially thickened up copper tube plates which are nccessary to ensure against tube leakages. It wais an obvious scqucl to weld the tube to the tube plate. The other plates are usually only 3/8in. instead of ½ in. necessary for copper, and therefore the loss due to non-conductivity is reduced considerably, and there is no discernible disadvantage due to the slight slowing up in the rate of heat transfcr.
4. The whole steel firebox can be stress relieved after welding and before insertion in the firebox shell for staying and tubing, and therefore there should be no inherent high stress.
5. Advantage can be taken with a steel firebox to eliminate the fire hole ring and even the foundation ring at the junction with which plates frequently waste, due to local overheating combined with localised stress. For large fireboxes thermic syphons can be welded in, thereby increasing the heating surface considerably and providing support to the crown sheet to supplement the crown staying provided.
6. Where weight is important, a steel firebox and its staying is lighter than a copper firebox.
7. Maintenance is eased as welding makes repairs by inserting new plates, a comparatively simple job.
8. One of the main troubles, however, with copper fireboxes is the tendency for the tube plate to be stretched and pushed upwards by the greater linear expansion, and particularly by the rolling of tubes. The maintenance staff are very apt to be the cause of this, when working in a hot firebox, with the result that the tube plate flange becomes distorted at the top and all sorts of serious troubles result. Even in the case of large main line boilers, this trouble has caused cracks in the top flange, particularly with fireboxes with combustion chambers, and although various methods are adopted to protect the copper tube plate, the steel tube plate does not suffer from these troubles and the crown staying is far simpler. Steel boxes are more suitable for direct crown staying.
9. The life of a steel firebox, provided water conditions are not corrosive or low in alkalinity, is often nine or ten years, which is half the life of the boiler. The copper firebox is unlikely to last the life of the boiler in spite of its longer life. 10. The reduced size of stay consequent upon the adoption of steel increases flexibility and reduces the obstruction of the water space, but it is the design of the comparatively short water space stays in steel which requires a very careful study, and this was considered at length.
Discussion: C.F. Ryan (494) said that the Author, in listing the advantages of the steel as opposed to the copper box, had said there was a marked saving in weight, and also an advantage in delivery. If one could use a higher tensile steel in this job, one could get a saving by reducing the thickness of the plate. One of the disadvantages with a screwed stay would be the loss of strength at the screwed portion, hence it might be possible to use a welded stay. Another disadvantage would be the corrosion danger, and the speaker was not actually aware whether there is a steel which would give better corrosion properties. There is a rustless 40-ton steel which has a higher tensile strength than the ordinary firebox plate, and equally good welding properties with the ordinary plate. Provided that the steel had better corrosion resisting properties than the existing firebox plate stecl, it occurred to the speaker that it may possibly be a good thing to experiment. He snggested that stainless steel might he used and hc asked if the Author would comment on the possibilities of stainless steel fireboxes.
H. M. MacIntyre (494) said that almost 30 years ago he had to take out copper boxes and change over to steel at the rate of about 4 to 5 per month. With regard to maintenance, steel boxes were very easily patched, so much so that when it came to modify numbers of boilers whicn were non-superheated, one simply cut out a portion of the tube area and welded a new piecc in. With regard to the thickness of the tubeplate, he agreed that 3/8in. should not be exceeded. Copper ferrules could be used on the tubes, expanded in the barrel followed by beading over and welding. He had nevcr thought of turning the boiler up on its end to weld, and had nevcr filled it with water, and he had had no complaints. He expressed surprise that no allowances were given for the tubes in the way of staying the tube plate. He was also surprised that the illustration did not show the hollow stays.
Journal No. 235
Vandy, W. (Paper No. 526)
The production of steel wagons. 502-31. Disc.: 531-9. plan, 5 diagrs., 26 illus.
Author was Works Manger, Shildon Wagon Works. Mass production techniques and widespread use of welding, including development of jigs and automatic welding machines.Illustrations include an iron ore tippler, coke wagon, hopper coal wagon, an experimental bulk cement wagon and a bogie iron ore wagon of the type used to Consett. Discussion: C.A. Gammon (532-3) noted that the LMS had employed mass production techniques to manufacture timber wagons from 1923.
T. Henry Turner (534) said that the Paper showed that the Author had inherited a very fine tradition in Shildon. He recalled the time when Mr. A. C. Stamer took the speaker round that works in 1930, and also the later guidance of Mr. Thompson, Mr. Peppercorn and Mr. Smeddle; but the man who stood out in Mr. Turners memory was Mr. Cruddas. He was a real works engineer and the pioneer of many things which Shildon Works did before other works considered them. His flash-butt welding was an adjunct to the smithy, bringing the smithy technique up to date. His multiple-head oxygen cutting was another modern way of helping the smithy. He introduced flash-butt welding for three-link couplings and fabricated steel axlcboxes, of which he was the pioneer, in these works which are located in the country, and which might therefore have been backward. Instead of that Shildon enjoyed a tradition of progress, and their workpeoplc stayed there and developed their own methods and tools in a keenly progressive manner.
Axleboxes-On the question of Shildon axleboxes, he had one criticism to offer, that he saw on the track too many of their doors open and coal slack in the bearing; something needed to be done to kccp the axlebox doors shut.
Corrosion-With regard to corrosion, it so happened that in the Shildon works a hundred 20-ton side door opening coal hopper wagons were built about 1939, in the sloping bottoms of which were incorporated symmetrically plates of four different steels; namely mild steel, copper-bearing steel and two low-alloy steels. This was done in conjunction with the Iron and Steel Institute Corrosion Committee, and a R.I.S.R.A. report on ten years of examination of those wagons was published by the Iron and Steel Institute some two years ago. It seemed to show that it would pay to use some lowalloy steels.
However, the percentage corrosion reduction offered by any lowalloy steels in thiy country or in other countries was still relatively small as compared with stainless steels and one was therefore led to consider improved methods of protection against corrosion.
Galvanising-Some years prior to nationalisation consideration was given as to whether the open goods steel wagons which Mr. Cruddas pioneered could not be taken piece by piece -and zinc coated in a hot galvanising tank, to show the mechanical engineer as a demonstration some completely galvanised wagons.
The civil engineer used galvanising of steel with good results as did the marine engineer, and even the automobile engineer when he built the Land Rover galvanised many of the exposed bits and pieces; but oddly cnough there did not seem to be a single British Railway mechanical engineering works which used galvanising, so it did seem that such a demonstration should be made.
Unfortunately the disturbances caused by nationalisation killed the idea at first, and then when it was taken up again by the late Mr. Pugson the price of zinc soared and it became almost unobtainable. Fortunately, however, zinc was now cheaper and obtainable once again so that tests with galvanising of steel wagon components were again a practical possibility. Figs. 2 and 3 showed components which could almost certainly benefit by being galvanised.
Thinning-If a component went out of service due to thinning, the thinning was not only due to abrasion on the side which wore by friction, but also on the other sides due to corrosion. To take, for example, an Instanter coupling, if it were galvanised friction would soon rub away the zinc at two places, but zinc had the property of preventing corrosion of the steel in its neighbourhood. Normally such a coupling would go out of service through thinning but if it were galvanised to prevent corrosion at the back, the coupling would remain serviceable for a longer time. Metal spraying could be used as an alternative in some cases either with zinc or with aluminium. For real protection against the corrosion difficulty mentioned by the Author at the beginning of the Paper, galvanising or metal spraying were better than painting.
Bearing Metal-It would be interesting to hear from the Author whether other Regions of British Railways were still using the former LNER carriage and wagon bearing metal with 56 per cent tin. That particular bearing metal was popular because of its excellent casting properties, and although mechanical tests had shown merits in other bearing metals, the former 56-60 per cent tin alloy was probably the easiest bearing metal to cast and so resulted in the minimum of defective bearings in manufacture.
Ell, Samuel O. (Paper No. 527)
Developments in locomotive testing. 561-91. Disc.: 591-633; 729-34 + 4 folding plates. 2 illus., 19 diagrs. Bibliog. .
Meeting in London at IMechE on 18 December 1953: R.C. Bond in chair
The thermodynamics of the locomotive is inseparably linked with the mechanics of the train. It was shown how this can be accomplished in locomotive testing in a manner both analytical and demonstrative. In describing its development it was shown (1) how the performance and efficiency of a steam locomotive can be expressed by a three-fold relation and by a two-fold relation in thermo electric units, and (2) why the mass, system of locomotive and train and its normal mode of progression must be preserved in demonstrative analytical testing. Since the normal mode of progression is one of variable speed, an outstanding problem has been the control of the thermodynamic factors at variable speeds. Finding a solution in apparatus and methods which are simple and easily applied, a full description and analysis was given of a test on the Controlled Road Testing System. How the results of a number of tests are coordinated was described and the paper concluded with a discussion of the implication of the results in respect to the efficiency of the locomotive as a mobile power plant and as a motive power unit with its associated operating problems.
Illustrated by tests conducted with King class 6001 using controlled road testing. On page 565: "Then, with respect to the steam rate-power relation, it was demonstrated that this is the Willans' relation. Every student of steam should, but usually does not, know Of the fundamental connection between the indicated steam rate and hypothetical mean effective pressure for the two conditions of governing by throttle and by cutoff. P.W. Willans, 60 years ago, showed that similar relations held for the practical engine and the distinctive curves for the two conditions are known by this name. And of course, it applies to the steam locomotive, though one may search its literature in vain for a mention of it": see also an Appendix and Paper by Willans..
Discussion: Stanier (pp 591-2): said he could not help thinking that if he could have had the advantage of some of the information now in the possession of designers and obtained by the careful analysis of the testing of the various thermodynamics and mechanical parts in the construction of locomotives, he would have been much happier in the work which he undertook. It was very interesting to see that the old dynamometer car, the underframe of which he designed when in the drawing office, was still running. He recalled that when he started in one of the drawing offices he had the privilege of working in the old dynamometer car. It was a four-wheeled vehicle with a fifth wheel for operating the mileometers, and it originally had a laminated spring something like a buffer spring. Mr. Pearson, who was doing experimental work, designed a spring built up of separate plates with rollers between the plates, and that spring was in the present dynamometer car. Therefore the work done by Mr. Pearson was still helping in the work being carried out at Swindon. He wondered whether the very interesting and ingenious method of obtaining the steam flow from the tip of the blast pipe which operated a gauge on the footplate might not be of some guidance to the footplate staff if they had to work the engine to the degree of accuracy and speed which he Author forecasted on his test. A thing which had puzzled him for a long time, having ridden on many engines, was whether the right practice was to notch up as close as possible and have a full regulator, or whether to let the gear out a bit and ease it on the regulator. He had never been able to solve that problem himself, and it seemed possible to find an answer. The impression he gained was that it was all very well to have a gear which could be notched up to 10 per cent and work at full regulator, but it put a good deal of stress on the gear, and drivers found that it was better to work at 18 to 20 per cent and ease the regulator. He desired personally to thank Mr. Ell for having presented the Institution with such an excellent Paper which would be a source of interest and reference for a number of years to come. In fact, as long as steam locomotives ran. Mr. Cock did not think that they would run much longer, but there was still life in them and the work done by the Author had put another period on their life because more efficient locomotives were bound to result from it.
Meeting at Midland Hotel in Derby on 8 December 1953: Chairman: R.S. Hall
A.J. Powell (616) said from the diagrams given in the Paper some indication of the effect of the exhaust injector could be deduced and it appeared to him that the use of the exhaust injector gave an increased steam output of the boiler of about 4 to 5 per cent. As compared, with a live steam injector, there was a fuel saving of something in the order of 10 to 11 per cent. Were the figures typical for fairly continuous working? Also, in that connection, he believed it had been known for the limited delivery of the exhaust injector to impose a restriction on the maximum output during tests on certain locomotives. Could the Author confirm and possibly say what effect there would be on the boiler performance of having to supplement the exhaust injector with the live steam injector?
The diagrams in the Paper were all in respect of the Great Western " King," and it appeared from the steam temperatures that a high superheat " King " had been chosen. Had any significant improvement been shown in the maximum output or in specific coal and water consumptions as compared with the original design of " King " with moderate superheat?
The Author said that the boiler limit was governed by the amount of cxccss air which could be brought into the firebox at high output and a figure of 15/20 per cent was mentioned. Did this hold good with most types of coal, for instance, Welsh and Yorkshirc? Was it possible to affect this limit. by, for instance, increasing the size of passage for secondary air through the firebox door without sacrificing efficiency at low outputs due to too much excess air, and also how did this tie up with the texhing on the London Midland Region of controlled firing? An official film had been shown on "Controlled Firing" and the fireman in that film was instructed to fire a moderate amount of coal, to leave the door open until the slight amount of smoke disappeared. Hc should then shut the door in stages watching the smoke at the chimney until it clea,red and then fire again. The Author might like to comment on that teaching.
On the point of the boiler water level being maintained to plus or minus 4- in., he thought this was a little misleading and that the Author had in mind boiler water content in total, rather than the level indicated by the gauge at any particular point, since no greater variation in gradient than from 1 to 300 up to 1 to 300 down would affect the level on a moderately sized boiler by about one and half inches. The Author, by implication in the Paper, suggested that constant steam rate working was not strictly practicable from the operating point of view on heavily graded roads, and that on long banks it was necessary to increase the steam rate above the mean. Would it be correct to suppose that such an undulating route as the London Midland Region, Midland Division main line south of Leicester, was not suitable for constant steam rate operation? If so, perhaps thc Author would comment on the feasibility of going to the opposite extreme of thrashing an engine up hill and coasting down hill to maintain as uniform a spced as possible. Was there any significance in that figure?
In Appendix I a formula for the efficiency of a single blast pipe and chimney was given, and putting reasonable assumptions into that formula it did appear that the normal blast pipe at low output had an efficiency in the region of 4 per cent and at high output of about 7 per cent. This was very much lower than would be obtainable with any fan system where figures of 45-75 per cent were common and was an interesting example of the convenient use of readily available waste materials for draught production in a simple device, even though very inefficient thermodynamically for that purpose.
J.W. Caldiwell (618) said there had been many different opinions about the Nationalisation of the Railways, and probably still were He thought that so far as the Midlands Centrc was concerned, it had been an unalloyed advantagc, in that, in quite a short time, three papers had been given by men from Swindon-Mr. A. W. J. Dymond on Operating Experiences with Two Gas Turbine Locomotive, Mr. K. J. Cook on G. J. Churchwards Locomotive Development on the Great Western Railway, and now Mr. Ell on Development in Locomotive Testing. He did not think Mr. Dymond had developed A.T.C. from the start, and Mr. Cook had confincd his Paper to what Mr. Churchward did. He understood, however, that Mr. Ell had actually instigated and developed the very beautiful method of testing which he had described and they were all very grateful to him for making it public.
He had read the Paper with great interest, and one thing he would like to ask was if the Author claimed that the variable speed method of testing was better than the constant speed road tcst or the stationary plant test. He could see that it was more convcnient than the constant speed road test because it did not interfere with traffic so much: Also, it did literally demonstrate that a locomotive could do a certain job, but apart from that, did it have any inherent advantage over the constant spced test or the stationary test on a fixed plant?,
Another point which was not clear was thc method of controlling the water level in the boiler to such small limits. The Paper implied that the control of the water level was not solely the responsibility of the engine crew, as a system of lights was mentioned to warn the crcw when the water level variation was approaching the limit.
In rcgard to the coal feed, the Author stated that immediately one incrcment was removed from the scuttle, another onc was put in, in other words, it was not dependent on time, it was only dependent upon the pressure gauge. If that were so, why was it so important to be so particular about the actual increments? It would not matter if a couple of buckets were tipped in at once, the fireman would still fire at the rate dictated by the pressurc gauge. The use of the pressure of the exhaust steam at the blast pipe tip as a criterion of the steam production and the casy indication of the former in the locomotivc cab and the dynamometer car by means of the air balancing dcvice was very interesting. He wondered, however, whether the system was affected when using the same amount of steam in two different ways, viz. high speed with early cut-off and low speed with late cut-off.
In conclusion he thought the Author was a little unkind when he referred to students who had never heard of the Willans law. He had heard of Willans and his famous line, but then he was gctting old. Young people would be more interested in the air standard cycle, and if they got as far back in history as the Otto cycle they probably thought they had done very well.
Mr. L. J. Brown (A.M.) asked if the tendency was for more road testing and less static testing; would the train crews be taught a different method of firing the locomotive, and would it entail more instruments for the footplate crew?
R.S. Hall (619) said they had been most interested in the facts and figures the Author had given them and remarked on the amount of work entailed in producing them. He was a little surprised that the Author had been able to obtain such uniform curves as shown in the diagrams because one would expect under road conditions and other extraneous factors that this would not be possible, however the results showed that observed points did lie on very smooth curves.
One of our great writers-it was either John Ruskin or Robert Louis Stevenson-prefaced one of his works with the remark that "Man's function in life was to find out." Mr. Ell had taken that very much to heart and had certainly done some sterling work in finding out what a locomotive could do, getting valuable facts and figures from dynamometer car and test bed readings and combining these with thermodynamical considerations, the results had formed the basis of a valuable Paper which had proved very interesting, and one which no doubt would often be consulted. Mr. Hall noticed in Fig 7 that the Author gave the chimney orifice as having an internal slope of 1 in 14. Was that the Western Region general practice? He had an idea that the chimney shape conformed more to a cone of 1 in 6 which was the cone of a jet of expanding steam; perhaps the Author had figures for other chimney cones as well.
Recently a speaker (a diesel engine enthusiast) at a meeting in Derby had mentioned that he thought the thermal efficiency of a steam locomotive did not exceed 10 per cent. Mr. Hall had then thought that this was perhaps an under-estimation, but from the slides shown it appeared that the statement was correct and that in general the Western Region obtained 9 per cent thermal efficiency constantly on long runs and as the Author's figures were very reliable it would appear that only in exceptional circumstances would 10 per cent be obtained.
Meeting in Manchesteer held at the College of Technology on 26 January 1954: Chairman Colonel G. Rigby
R.C.S. Low (730) said that he noted from one of the slides of a King Class locomotive on the test train that there appeared to be a loss of water from the injector, and he wondered whether this water was metered in any way. He also asked for further information of the Swindon Flow Meter. Reply: The wastage noted by Mr. Low in a photograph of a test in progress was of exhaust steam due to a leaking valve of the exhaust steam injector which was not then in use. Water overflow is automatically metered before rejection. The flow indicator is used by the driver to control the working of the engine by the cut-off so that the demand made on the boiler by the cylinders remains constant throughout. The water evaporated is obtained by direct metering of the water injected; this rate should be constant because the rate of steam demand is kept constant by the driver.
W. Bradley (730) said that he entirely agreed with, the Author that the greatest economies were to be found by properly planning engine diagrams for continuous service, and following up to ensure that speed schedules and timings were maintained. It would be found that the great body of enginemen were behind any attempt to keep trains in motion, for nothing was more irksome to them than detention at signals, and nothing indeed was so expensive in all phases. He recalled that at one depot at which he was stationed, the overall coal consumption usually averaged around 58 to 62 lb. per mile, but on one occasion after a period of fog, during which the mineral trains were held up for considerable periods at signals, and then allowed to draw up slowly to the next with heavy expenditure of steam, the coal consumption shot up to 110 lb. per mile. These facts require to be pressed home to signalmen, as well as to diagram arrangers. It is found possible to arrange long, continuous work diagrams for high priced alternative forms of motive power, in order to justify the initial expenditure, we should use the steam locomotive in the same manner. There are now available powerful steam locomotives which are, without question, efficient mixed traffic machines. The diagrams should be built up around them, to keep them away from locomotive depots except for recoaling and washing out. That and keeping them moving is the way to economical working.
Bradley also asked if it was proposed to tutor enginemen in one standard method of operation? If so, what was that method? Would the Author advise working the engine with fully opened regulator, and governing the output by "notching" up the valve gear, or would it be permitted for the driver to regulate his speed by means of the regulator? Locomotives worked in the latter manner certainly kept in good mechanical condition longer than those worked regularly with the full regulator opening, and there was no noticeable difference in coal consumption. Had the Author any coal consumption figures bearing on this subject?
Reply to Bradley :enquires about efficient methods of working the loco- motive. The boiler produces more steam per pound of coal if the firing rate is matched closely with the real rate of coal consumption, i.e. by what amounts to "controlled firing" methods, but maximum boiler efficiency is obtained for the duty required of the locomotive- when, with these firing methods, operating conditions permit the steam demand to be steady and regular, varying little with gradient. These conditions are also highly conducive to maximum economy in the use of steam, but having regard to the effect of smooth running on maintenance, the optimum or best driving method is to work at as: high a steam chest pressure as smoothness of running permits. This rule is a better guide than regulator position. In fact at light rates of working, full regulator with a very short cut-off is neither economical in steam nor productive of smooth running. On the other hand, relatively long cut-off with partial regulator and low steam chest pressure is definitely not economical in steam. Whilst none of this is new, it has been confirmed by both analytical tests and observational trials of revenue earning trains over a number of years. Mr. Fo·re questions whether the time schedules of trains running on steeply graded lines can be calculated from the results of Controlled Road Tests made over less steeply graded routes. To find the equivalent load on a steep gradient to correspond to a steam rate and speed which by demonstration has been shown to correspond to a heavier load on an easier gradient is merely a technical calculation involving no question of principle. It is not necessary for the test to take place over the line for which the schedule is required, whether the line be suitable or not for this purpose, but it is essential that the test should take place on a route where continuous steam and coal rates can be kept for a period long enough to quantify the rates. Controlled Road Tests epitomise, if they somewhat idealise, the economy attainable by what is the equivalent of " controlled firing" when combined with a steady steam demand and the efficiency attain- able by feeding steam to the cylinders at a steady rate and at the maximum practicable steam chest pressure.
J. Fore (730-1) spoke of the ex-LMSR Class 4F 0-6-0 which had had its blastpipe and chimney redesigned to Swindon specifications and had completed steam tests recently over the North Wales main line. The modified draughting arrangements had raised the maximum continuous steaming rate from about 12,000 lb. /hour obtainable with a normal engine of this class to almost 21,000 lb.v hour. He would like to compliment Swindon on this achievement, being but one of the many successes scored through the careful thought and research which had been devoted to this subject over a number of years. Commenting on the arranging of timings to give a constant steaming rate, or as nearly constant steammg rate as possible Mr. Fore remarked that the whole of the tests shown had been based on the London/Bristol road of the Great Western, and he said the gradients there were nothing when compared with the gradients encountered north of Crewe, and negligible when compared with the gradients encountered in the Northern Division of the LMS. He doubted whether a constant steaming-rate schedule would be practicable between, say, Carnforth and Carlisle with the 31-mile climb to Shap followed by a similar length. of downgrade to Carlisle where the steaming would be hardly one-third of that needed for the climb.
Mr. Fo·re questions whether the time schedules of trains running on steeply graded lines can be calculated from the results of Controlled Road Tests made over less steeply graded routes. To find the equivalent load on a steep gradient to correspond to a steam rate and speed which by demonstration has been shown to correspond to a heavier load on an easier gradient is merely a technical calculation involving no question of principle. It is not necessary for the test to take place over the line for which the schedule is required, whether the line be suitable or not for this purpose, but it is essential that the test should take place on a route where continuous steam and coal rates can be kept for a period long enough to quantify the rates. Controlled Road Tests epitomise, if they somewhat idealise, the economy attainable by what is the equivalent of " controlled firing" when combined with a steady steam demand and the efficiency attain- able by feeding steam to the cylinders at a steady rate and at the maximum practicable steam chest pressure.
The application of the results to such cases as were mentioned by Mr. Fore involves the introduction of no new principle. Bearing in mind that, within the economic conversion band of the locomotive the steam rate is not very critical in respect to efficiency, the rate may be reduced to meet a speed restriction, or steam may be considered as shut off altogether if this involves reduction below the minimum rate of the economic band. Over these very routes the LMSR in 1946-47 carried out tests; the coal and steam consumption of the most economical runs plotted against time show a striking resemblance to Fig 3 when interruptions imposed by practical track features are taken into account. The same tests showed that because an engine appears to be working heavily at slow speed on a steep rising gradient that its steam rate is necessarily higher than the average and that when it is running at high speed, notched up and with restricted regulator opening, that its steam rate is necessarily lower than the average. Hence the introduction some years before of the scheduling of trains on the steam rate system on the former GWR and present Western Region was successful because it involved no new principle of locomotive handling, only the best of what was already known applied in a technical form. The system was and is as successful over those parts of the Region which, because of their heavy grades, produce problems at least equal in magnitude to those mentioned-by Mr. Fore.
D. Patrick (731) referred to the Author's reference to controlling the water level to ± 1/8 in., and asked if it had not been found difficult to obtain what were called still water conditions, havmg regard to the way water surged, ebbed and flowed in the firebox, and he asked what provisions were made for the actual variation in the water level due to the changing gradients. In connection with front ends, Mr. Patrick asked if a nozzle fitted with tips, commonly known as "Goodfellow Tips," had been tried and with what results. Continuing, he said that some of British Railways locomotives were fitted with diaphragm plates like the American Master Mechamcs front end and asked how evaporation of the boiler with diaphragm plate ends at both ends compared with .none at all. Also, were. any tests made on the oil burning locomotives and if so did any mterestmg information emerge on oil burning as against its counterpart, coal fuel?
Journal No. 236
Tuplin, W.A. (Paper No. 528).
Some questions about the steam locomotive. 637-65. Disc.: 665-714: 1954, 44, 167-73. illus., 10 diagrs. 3 tables.
Most of this paper, including the monumental, but mainly destructive commentaries by Carling, Ell and Holcroft are considered on the Tuplin page and are not repeated here. An outsider's (but a professional engineering outsider) view of locomotive development. The paper is interesting in that all of Tuplin's views more widely aired in several books and many magazine articles were subjected to scrutiny by professional locomotive engineers (thus the response is especially interesting).
Tuplin argued that the extra weight demanded for stronger boiler plates invalidated the "advantage" of adopting higher boiler pressures. The following Tuplin criteria were subjected to Tuplinesque scrutiny by Carling:.
(a) The higher temperature of the water means higher temperatures
in all the main components and this can affect the copper firebox and copper
stays appreciably as that material begins to lose strength as the temperature
rises above about 300°F.
(b) The higher temperature and pressure of the water accelerates any chemical action of its impurities on the boiler.
(c) The thermal stresses in critical parts of the firebox wall may be increased by the effect of the greater thickness.
A key feature of Tuplin's paper, and one debunked by Ell was Table III best speed ranges on page 647 wherein the best speed range in terms of boiler/cylinder capacity and the best speed for valve performance were listed together with their overlap if any: there was alleged to be none for the GCR Director class, and only the range 50-59 for the King class: the latter was clearly perceived as a red flag by a bull by Ell!
Two cylinder designs were advocated as against the use of multiple cylinders: if multiple cylinders were adopted then he favoured the layout employed on the B16/2. Favoured narrow fireboxes and the absence of trailing axles. Cited Goss (this got him into a lot of trouble) to advocate the use of simple front ends as aginst multiple blastpipes and chimneys. He made a number of comments on the ergonomics of cabs and the operation of firehole doors.
Discussion: H. Holcroft (665-8) opened the
discussion and on page 666 (when well into his response) Holcroft noted that:
"In the Paper much prominence was given to thermal efficiency per se.
To the locomotive engineer, however, thermal efficiency was only one factor
of many and it had to be considered with due regard to all the others which
went towards the making of optimum power. It might well be
that in the end some sacrifice of thermal efficiency could be beneficial
in producing the most suitable motive power unit. Holcroft was highly critical
of Tuplin's assertions concerning low boiler pressures: "such engines were
amiable and reliable machines but most lethargic" Holcroft was also highly
critical of Tuplin's observations on firing methods, on superheaters, and
on lost motion in valve gear due to excesssive clearances (and cited his
own measurements to show that was not the case).
C.C.H. Wade (668) commented on firing techniques and the limits of endurance for firemen.
R.G. da Costa (668-71) was highly critical of Tuplin's observations on superheating, and in particular Tuplin's attempt to relate grate area to superheater surface and temperature; Tuplin's interpretation of Goss's observations on unconventional valve gear which da Costa considered had been made prior to what da Costa stated were "substantial improvements" in the design of valve gear, especially in poppet valves.
S.O. Ell (671-4) see Tuplin page.
Pelham Maitland (674) recorded that in a large number of instances where the boiler pressure had been raised there had been an immediate and, in aggregate, appreciable saving in coal consumption. On firing engines with wide fireboxes, the technique of firing to the four corners of the firebox and little elsewhere produced one outstanding feature. It tended to the more thorough combustion of the coal than otherwise would be possible, because the draught did not tear the fire to anything like the same extent as with a narrow firebox. That was a feature on which he would like the Author's comments-the tearing of the fire in a narrow firebox as compared with a wide firebox.
A. Hood (674-6) noted that Tuplin queried whether boiler designers set themselves targets regarding weight per unit of heating surface. So far as the private builder is concerned the answer was an unqualified affirmative inasmuch as the weight limitations imposed by the clients' specification set the target. Only those closely acquainted with the subject appreciate fully what these limitations mean, particularly when restrictions are placed on the. weight per foot run of wheel base as well as on axle loading. In the remarks on fireboxes Tuplin made no comment on firebox volume: it has been argued that much of the merit of the narrow box is derived from the ratio of volume to grate area being good, and the more general adoption of the combustion chamber seems to substantiate this. In fact it has been claimed that the narrow box is practically the ideal shape when dealing with oil-fired locomotives.
With regard to the comparisons of boiler weights, as given in Table 1, it may be suggested that a much more equitable basis of comparison might be to make this in terms of evaporation per hour from the various boilers. This would bring into play the division of the heating surface between the firebox and tubes. Such a comparison might be made either on the basis of any agreed rate of evaporation from the firebox and tubes or preferably on the basis of the recently published data on locomotive testing issued by British Railways.
The comparisons. made in the Paper are only fair if the locomotives are designed to the same ratios of fireboxes and tube surface. In a recent locomotive built in this country for overseas the total evaporative heating surface is in fact less than in a previous design, and the tube heating surface is some 4% less, yet the new design has permitted an increase of 40% in the firebox heating surface.
The concepts of "nominal speed," "specific speed" and " specific. effort" are highly interesting, but whether there will be general agreement with the conclusions which Tuplin derives from his analysis is open to question. Nevertheless, the argument put forward is worthy of close study.
There is probably no more debatable point in locomotive design than front end proportions, and also nothing which can so influence the performance of the locomotive in service, yet it would still seem that the only guide is experience based on previous designs, for despite the fact that the American Master Mechanics' proportions have been known for many years, it would seem that even in the USA there was nothing really standardised, at least tliat is the conclusion arrived at after studying the results of the front end experiments made in the University of Illinois, and Johnson seems to confirm this in his book on the Steam Locomotive.
While the Author's criticism of the 4-6-2 type on the basis of weight transfer may, perhaps, bear analysis for locomotives on British Railways, it cannot be applied to locomotives for railways where the permissible axle load is a limiting factor. Would the Author. faced with the problem of providing for a large boiler on a passenger locomotive, prefer to use a 4-8-0 with all it involves in the way of extra rods and resistance in preference to a 4-6-2 if the 6-coupled engine gives all the ,adhesion necessary? , As regards mechanisms one can readily agree with Dr. Tuplin when he says" the less of it the better," so why not go all the way and adopt servo motors which would put the steam locomotive driver on a par with his opposite number on other forms of power? .
The Author had referred to ash chutes for smokeboxes. Two past applications of this idea sprang to mind. Paget's 2-6-2 engine of 1907 had used such a chute, sealed at the top by a simple flat-seated plug held by its own weight in the top of the chute and with a long-lifting handle. Even simpler was the device used by F. W. Webb on his" Precedent" and 3-cylinder compound passenger engines, consisting of a chute tapering down to a rectangular hole about 6 in.x 2 in. quite open to the atmosphere! No attempt at sealing was made, but the front plate of the hopper was extended some inches below the back plate and turned over to give a crude ejector action due to the air stream when running forwards. He was not aware of any complaints of the steaming of the" Precedents," but would be reluctant to see such a device applied to modern locomotives!
He felt he must join issue with the Author on the subject of regulator operating mechanism. Whatever -the torque might be on the shaft to operate the regulator, the pull at the cab to overcome it would, of course, be the same if the mechanical advantage of tire existing and proposed linkages were the same. However, the weight of the operating rods alone on the" Britannia" boiler was of the order of 70 lb., and in view of the damage caused to them by cleaners standing on them, etc., he did not see that they could be lightened satisfactorily. Did the Author seriously suggest that the direct pull necessary to a~celerate this mass in opening the regulator would permit anything approaching the present sensitivity? He thought the Author should be copdemned to an eight-hour shift shunting with an .engine so fitted! In conclusion, he felt that drivers would rebel at the Author's suggestion to bring the cab window back close to where they sat. One thing that was very necessary in case of emergency was complete freedom of movement in the cab, and criticisms of the BR standard cab layout which had been voiced dealt with the driver's sense of being" boxed in " by the grouping of controls round him. With the proposed arrangement, the driver would be risking his skull even to tie his bootlaces!
Mr. P. R. Saunders (678-9) wrote that the Author pointed out that a 4-6-0 locomotive, particularly one with a high drawbar, would be better in some circumstances, such as starting on an up gradient or on an irregular track, than a 4-6-2 of similar nominal adhesion. The implication of this part of his Paper was, he assumed, that it was sometimes preferable on this account, to build a 4-6-0 rather than a 4-6-2, both engines having the same weight for adhesion. He would suggest, however, that 4-6-2's were only built when it was absolutely necessary from a consideration of the work required of the locomotive in other circumstances. The 4-6-2, with a larger firebox and boiler, would have a superior performance at speed, when maximum adhesion was not required, and may yet have a greater availability. In any case, Professor Tuplin's calculation of the weight transfer that took place would appear to be in some error. Since the coupled wheels were separately sprung, and the trailing axle had greater loading than the leading axle, this weight distribution among the coupled wheels exerted a levelling moment on the frame which was neglected when only the overall transfer of weight from the bogie wheels was considered. A calculation, taking that into account, showed that the transfer from idle to coupled wheels for a BR Class 5, 4-6-0 when the drawbar pull was 12 tons at 3½ ft. above" rail level was less than 1¾ tons, rather than 2½ tons.
W.O. Skeat (679-81 written communication) see Tuplin page
M.A. Henstock (693) argued that the reserve available with higher pressures was appreciated by the footplate crews; he noted that the LMS used nickel steel for some its boiler plates to reduce weight; he commented on eddy currents above the brick arch; and noted the problem associated with short connecting rods: heated bearings and crosshead wear. He did not understand the criticism about the" Patriots" and the" Royal Scots," they certainly have the same wheel diameter and cylinder sizes, but the tractive efforts were far from comparable, the first being 26,520 lb. and the latter 33,150 lb. This seemed a very big difference by which to compare a locomotive. The L.M. Region 2-6-0 Class 5, parallel boiler engine with a pressure of 180 lb./sq. in. and tractive effort of 26,580 lb. could be compared with the 2-6-0 Taper Bqiler Class 5 which bad a tractive effort of 26,288 lb., these two locomotives were, in his opinion, far more comparable to bring out the points that the Author was trying to make. Regarding the diagram showing the fire hole door, as he did not understand how it worked he asked if the Author would be good enough to give an explanation.The inward opening door was not a new idea. All the former L & Y Rly. engines had inward opening" flap" doors and one of the main disadvantages was the frequent renewal of this type of flap which burnt away very rapidly.
The diagrams of the regulator operating rod reminded him of what all designers should avoid, a "one view" scheme. The arrangement shQwnin the elevation looked no doubt feasible, but if the plan view of the boiler and rod had been shown a different picture would present itself, due to the rod having to pass the widest part of the firebox and 'be straight in the plan, t~e shaft at the multiple valve header would have to be extended considerably to line up the lever with the operating rod; this overhang was very undesirable on account of wear taking place and causing the gland packing to leak even more than at present.
The load required to open the pilot valve was 250 pounds and by the existing arrangement there was 'no chance of the rods being moved by anyone or anything from outside the cab.
If the Author's scheme could even be adopted, the chances were that this could result in the regulator being opened other than by using the handle in the cab, which would be very undesirable, especially when the engine was being serviced at the sheds, due to the possibility of the regulator being opened by some unauthorised person, cleaner, etc.
The Author unfortunately had not given anything concrete on which the designer could base a design for the smokebox; the diagram of smokebox proportions was like most, it fell short of giving the blast pipe cap diameter, or anything on which to base it for a given locomotive, the distance from the tubeplate and also the height below the centre line of the smokebox; these were the figures the designer had to search for, and how elusive they were.
D.R. Carling (694-8) see Tuplin page.
W.G.F. Thorley (698-9) noted that Tuplin stated that the object of superheating was to ensure that, despite the drop in temperature of the steam as it expanded in the cylinder, it did not become saturated. Could it not be said also that the superheater provided also a valuable addition to boiler steaming capacity inasmuch as the volume of steam was increased by its use? It would be recalled that the first two "Princess" class Pacific locomotives of the former LMS Railway had 32-element superheaters fitted in place of the original 16-element apparatus after only a short period of service, and the steaming was improved thereby. The Author had said in the discussion that the firebox volume was increased at the same time as the additional superheating surface was provided and therefore the value of the latter could not be assessed accurately, but in this connection it was pointed out that the number of elements had been increased without increase of firebox volume in both the Classes 5MT and 5XP locomotives of the same railway, as 'compared with the original arrangement and the steaming had been improved. The superheater had the advantage that, provided the flue tubes were kept reasonably clean, its efficiency remained unimpaired as the boiler scaled up internally; also it was sometimes able to evaporate water during periods of priming, which would be carried over into the cylinders of a saturated engine.
The Author recommended a 3-cylinder engine having the inside mechanism as readily accessible as that of the two outside cylinders and the B16/2 4-6-0 Class of the former LNER was instanced as an engine which nearly gave the desired feature of being able to be prepared without the use of a pit. It appeared, however, that in these circumstances the driver would have to pass between the trailing bogie wheels and the leading coupled wheels to gain access to some of the inside oiling points and this was a practice which could not be officially countenanced.
Mr. Thorley considered that the Western Region practice of lifting the flap plate between the application of each shovelful of coal, as mentioned under "Firebox" in the Paper, was brought about more by force of circumstances rather than by any conviction of the enginemen that it was the correct thing to do. Whilst such an attitude of mind on the part of the latter was a very good thing to encourage, the fact remained that if an engine would steam freely with the flap remaining down between consecutive shovelsful, then the flap remained down.
Meeting in Glasgow, 26 January 1954: A. Hood:
(704-5): noted that the first Merchant Navy class boiler was designed
and built in Glasgow, and at the request of the customer a second edition
of the boiler was designed and constructed which proved to be approximately
2 tons lighter than its predecessor. This was a typical example of the designer's
art which reduced the weight of the boiler yet maintained its original output.
J. Campbell (705) emphasised that higher boiler pressures provided "ample
reserve capacity. Considered that the inertia effect in valve gears noted
by Tuplin could be used as an argument against conjugated valve gears. E.F.
Clark (706-7) mentioned that comparison was seldom made between
steam locomotives and stationary reciprocating steam engines.
In this connection it was interesting to recall that on the
question of high superheat there were very few cases of steam temperatures
over 600°F. being used in stationary engines, especially those with
cast iron cylinders. The locomotive engineer tended to look at the performance
of the locomotive from the point of view of tractive effort, while on the
other hand, although for stationary engines conditions were different, engineers
considering them looked at their performance much more from the point of
view of steam flow and power output. On the question of eliminating unnecessary
mechanism, he suggested that exhaust valves could be cut out quite easily
by the adoption of the Uniflow system. He said that he thought all locomotives
would benefit enormously when rolling stock was fitted with roller bearings
and rail joints were eliminated by track welding. During a recent visit to
Germany when riding on a train which was admittedly hauled by an electric
locomotive, but on which the whole of the stock was fitted with roller bearings,
he had been most surprised to find that when the speed of the train had been
reduced to a walking pace, the whole train rolled on for a surprising distance.
He was quite sure that power was no being applied and this rolling on could
not be obtained with stock fitted with plain bearings. It was said that there
was no lessening of tractional resistance when roller bearings were used
over about 25 m.p.h., yet all trains had to be accelerated from standstill
to this speed. He thought there was a strong case for remembering that all
locomotives would benefit greatly when all stock was fitted with roller bearing
N. McKillop (707-8) With regard to the statement made by the Author that there were no means of comparing lower pressure boilers with higher pressure ones, McKillop said he was of the opinion there was a very good means of comparison. He believed he was right in saying that the first Gresley Pacific had a low pressure boiler and that eventually high pressure boilers were adopted, and the difference in performance was fantastic; very much less coal was burned and the mileage between shop overhauls increased from something like 60,000 miles to 102,000 miles in certain cases, which was due, in his opinion, to the high pressure boiler With regard to wide and narrow fireboxes and fallen brick arches McKillop asked if the Author did not agree that wide fireboxes were an advantage in the event of the brick arch falling. He also said there was no difficulty in maintaining steam with the wide firebox.He said the Author had not mentioned anything about the combustion chamber Gresley introduced to the Pacific engine. With regard to piston valves, McKillop said that on the indicator diagram the sharp corners were produced by large poppet valves opening instantaneously by cam gears and he asked if the Author thought there would be an improvement by the operation of piston valves by cam gears. He said he was rather surprised to find that Professor Tuplin thought the efficiency of operation of a locomotive fell when the engine was taken above 15 per cent cut-off. In practice it was a fact that very high efficiency of the Gresley valve gear could be obtained with much higher cut-off. With regard to window design, which was very important, McKillop suggested placing the glass at the rear of the tunnel instead of at the front. He said it was surprising that Professor Tuplin had criticised the throttle operation on the engine, because he must know that the throttle operation of a locomotive was a very vital thing to a driver. The driver, going at high speed, must get a fine adjustment of the throttle, and if he had the assistance of a steam-chest pressure gauge it was necessary that he ran a distance with the throttle so adjusted, as he could make it fluctuate between, not 25 lb. or 50 lb. of pressure, but 1 lb. of pressure. He said the device introduced into the throttle rod was done to give rigidity and putting the brake handle where the Author suggested reminded him that on one occasion the little window, where he suggested putting the brake handle, was smashed by a passing train. It was a highly dangerous practice to put any apparatus outside a fast moving engine for a driver to put his hand on. He thought the operation of the firedoor by the driver was fantastic. He asked if it was not the case that Gresley introduced the combustion chamber on the Pacific to prevent the tubes warping, as it was found that the tubes were liable to warp and leak very badly, and a short rigid type of boiler tube would reduce such leakage.
A.C.D. Malcolm 708) said he thought the Author would agree that the trailing truck helped to keep the engine on the rails, which had been proved on at least two classes of engine.He said he thought it was better to have a steady back end and that Mr. Hood had a very strong point there, and he asked if the Author thought the fitting of a Cartazzi truck justifiable, as a trailing truck improved the riding of an engine.
D. MacAulay (708) mentioned Cartazzi slides and firedcors. In his experience in India the Cartazzi slide slid so much that the engine used to leave the track. With regard to firedoors, the standard design of firedoor was a scoop turning inwards and connected to a handle by a trigger. This was also in use on the same Indian Railway. The fireman had to shovel each shovelful of coal with one hand and work the scoop with the other, and he kept a very constant steam pressure in the boiler.
Meeting in Newcastle-on-Tyne, 24 February
F. Johnson (712) asked the Author to comment on the fact that it was not so many years since all boilers had narrow fireboxes tending to keep the cylinders small, making it easier to increase power by raising the boiler pressure. He pointed out that it must not be forgotten in connection with weights that with an increase of 15 per cent in the boiler capacity, to a boiler of the same weight, the lower pressure would call for an increase in the weight of water. If the boiler pressure were increased with the same size cylinder there should be an increase in the heating surface and grate area if the same power were expected from the locomotive. If the plates were merely thickened the same amount of coal would be burnt in the firebox and the same horse power created. He said that he thought that a greater superheater area was necessary for a locomotive which ran on a very short cut-off and he asked the Author to comment on this point. On the question of the transfer of weight with advantage to trailing bogies Mr. Johnson said that in his opinion the whole of the weight would not be taken by the trailing bogie. It would only be a portion of the weight. In commenting upon the regulator mechanism Mr. Johnson stated that so far as he was aware the regulator handle was often fitted with a trigger and locking ratchet and there should not be any necessity for an allowance for expansion as the regulator was only used when the boiler was in steam. In reply to Mr. Johnson the Author stated that he did not see how the firebox need control cylinder sizes. If big cylinders were wanted, the frame could be set in at the front end, and then the outside cylinders could be 25 inches in diameter if the connecting rods were placed against the wheel-bosses. When the size of the boiler and the speed-range for maximum power have been decided, the nominal tractive effort for highest cylinder efficiency in that range can be determined. The next step was to select the largest convenient cylinder volume and then to use the conventional nominal tractive effort formula backwards to find what pressure had to be provided to produce the desired nominal tractive effort in those cylinders. If only two cylinders were used to get the nominal tractive effort, the pressure might work out at 250 lb. per sq. in. as in the Class 7 Pacifies, whereas three cylinders would give the same result with about 185 lb. per sq. in. The Author said that boiler power is not determined by steam pressure but by grate-area and heating surfaces. It is true that a larger boiler holds more water and so the estimate of the boiler power possible within a given weight is not correctly based on empty weights of boilers As Mr. Johnson said, this fact reduces the possible gain in power/weight ratio from reduction of boiler pressure. The Author agreed that the higher the expansion ratio the higher the minimum desirable superheat, but added that shortening the cut-off below about 18 per cent does not raise the expansion ratio. He added that even the small superheaters used on the GW were evidently adequate for short cut-off working, at least with good maintenance.On the question of weight transfer the Author said that even if the springs of the rear truck and the preceding axle are equalised, the drawbar pull still transfers some weight on to the rear truck and therefore off the other wheels some of which may be driving wheels. If there is no rear truck, weight cannot be taken off the driving wheels by the drawbar pull, ,and so a 4-6-0 has some advantage in this respect over a 4-6-2. Regarding Mr. Johnson' s observations on the regulator rod mechanism the Author said that this was a good point. As expansion was small, the difficulty could in any case be got over by putting a locking trigger at the back end .
C.H. Swan (712) said that he had listened with interest to Professor Tuplin's remarks on the B.16 Class short connecting rod and from personal experience he knew that the great disadvantage was the short life of the little-end bushes; he suggested that the little ends should be fitted with roller bearings. In regard to the transfer of weight there was another factor to be taken into consideration. From the enginemen's point of view a Pacific is a much better riding engine than a 4-6-0 and from the maintenance angle the lateral wear on the trailing boxes is not normally so great on Pacifies. Mr. Swan said that a number of the uggestions made by Professor Tuplin were obviously very good as they seemed to adhere to former NE practice such as the Blades firehole door which hinged inwards from the top and closed with its own· weight, and there were the former NE type windows which opened inwards. The Automatic Train Control device mentioned by Professor Tuplin resembled the handle of the Ravens Fog Signalling apparatus which did away with the necessity for fog signalmen between Shaftholme and Berwick. The former NE vacuum handles could be reached from the window
Mr. Meicher (713.) asked if it were not possible for the therma efficiency of the locomotive to be increased by devoting further study to the volume of the smokebox.
Mr. Sadler (713) asked if Professor Tuplin could offer any explanation for the apparent reluctance to accept GW practice pointing out that. Gresley had to change a design after twenty years to fit with Churchward's design. Had it anything to do with boiler pressure?
De Sousa, C.H. (Paper No. 529)
The design of Indian Railways passenger coaching stock for greater comfort. 715-24.
The principal conditions which militated against comfortable travel in India were: climate, dust, noise, inadequate accommodation and lack of amenities,, and by implication the misuse of such amenities, notably wash basins and lavatories. The author considered that insufficient attention had been paid to the Indian's wish to sit with their feet tucked up.