Journal of the Institution of Locomotive Engineers
Volume 16 (1926)
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Journal No. 73 (January - February 1926)
Case, Robert C. (Paper No. 188)
Statistics and coal consumption. 4-37. Disc.: 38-41. 3 tables, 9 diagrs.
Presented Manchester on 27 February 1925 chaired by Haigh.
Statistical analysis of coal consumption in India at one depot with especially favourable characteristics. Considerable attention was paid to the statistical methods adopted. Factors included locomotive type and intended duties, and whether superheated or saturated. Freight was worked by 0-6-0s, but passenger traffic was worked by 4-4-0s. 4-4-2s and 4-6-0s. Suburban traffic was worked mainly by 2-6-4Ts, but some was worked by 4-4-2Ts. According to this statistical analysis there was no clear advantage to be gained from superheating on suburban tank engines. In other work it was possible to analyse the cost advantage of superheating. The effects of speed, locomotive weight weight, train load and locomotive maintenance on coal consumption were identified. In the case of goods (freight) engines superheating showed a clear advantage. Sopme consideration was given to coal quality, rates of acceleration and draughting.
Discussion: F.W. Attock (38-9). was cautious in noting that it was difficult to measdure coal consumption. He supported Case's observatiuons on superheating locomotives used for suburban services and cited Hookham's paper (Paper 126) . J.N. Gresham (39-40) examined the modern locomotive chimney and liner (if any) and found it insufficiently large in diameter to pass all the air necessary for satisfactory combustion together with the exhaust steam. Should the blast pipe become, or be set, slightly out of centre with the chimney, a very marked drop in smokebox vacuum will result. To obviate this, one of the Swedish railways made them integral in one piece. G. Brooks (40) the Author statet that fuel represents about 50% of all running costs, excluding main shop repairs, and therefore he could not understand why feed water heating had never come into prominence in Britain, whereas in Germany most engines are so fitted, as also in France.
Cochrane, J. (Paper No. 189)
Water: its occurrence on the Central Argentine Railway. 47-91. Disc.: 92-111.
Presented in Argentine on 17 April 1925 chaired by M.F. Ryan
Discussion: Louis Greaven (101-3, Darsie,. Anderson & Partners) noted the conclusions from a committee appointed to report on boiler feed waters in the USA which divided waters into:
Alkaline waters causing foaming and corrosion
Hard and incrusting waters
Soft and non-alltaline waters,
Kimberley, R.E. (Paper No. 190)
Notes on the organisation and working of a running department. 124-49. Disc.: 149-89.
Argentinian conditions. Fuel and staff (engine and shed) costs were the two biggest factors: both could be in excess of 45% of total operating costs. Water quality was frequently poor.
Reid, R.W. (Presidential Address)
Developments in coaching stock construction. 192-7. Disc.: 197-220; 277-94.
Mentioned the development of articulated rolling stock on LNER. Noted that demand for greater comford had led to increase weight. Noted use of steel in coach construction. Steam heating had added to the cost, and electric lightin placed a greater load on the locomotive. Unusual address for amount of discussion included. Kelway Bamber (198-9; 277-94) advocated bogie wagons which would lead to a 28% reduction in dead weight. S. Symes (204-5) noted the cost of carriage heating and commented on steam pressure employed; E.W. Selby (295-6) described the Bury electric rolling stock.
Journal No. 74 (March-April 1926)
Haigh, J.H. (Paper No. 191)
Fractures of locomotive parts. 230-8. Disc.: 238-47. 4 illus.
Fractures caused by bending, torsion, shear and in tension are illustrated. A high proportion of failures in parts subject to shock takes place in the screwed portion, as in brake work and drawbars. Some spring hanger bolts are so designed and fitted that they are subject to slight but frequent bending stress, resulting in flaws commencing at the bottom of the thread from the two oppositc sides extend until fracture take place. The stripping of threads either on the bolt or in the nut was occasionally a source of trouble.
Saunders, P.H. (Paper 192)
Principles and practice in the erecting shop. 248-67. Disc.:267-75; 662-74.
Presented in Leeds on 20 November 1925 chaired by Kidd
Frames; frame straightening and cylinder setting; bolting up; fittings. It should be arranged that heavy fittings such as brakeshafts, sandboxes, slidebars, etc., which come between the frames, should be placed into position before the boiler, to save time; testing the boiler; adjusting the safety valves; lowering boiler into place; horns, axleboxes; wheeling; motion work, valves and valve setting (covered at length)..
Bartram, J.H. (Paper No. 193)
Locomotive frames (a comparison of types). 299-308. Disc.: 309-12. 7 diagrs.
Presented in Manchester on 4 December 1925 chaired by Kidd
Frame evolution. The first locomotive had no frame, the boiler providing the attachment for the cylinders and wheels. Springs and brake gear were unknown, but independent frames were soon introduced and springs and brakes added. Built-up frames, of wood with wrought iron flitch plates, thin plates riveted together, cast iron frames, welded bar frames, forged, slab and double frames were used and gradually developed into the modern frame. An early defect in the design of the locomotive was the rigid connection of the frames to the smokebox and firebox, and it was also a common practice to couple the drawbar to the rear of the firebox. This system proved a permanent source of boiler trouble that was only remedied by making the frame self-contained and resting the boiler upon it so that it could expand freely. The slab plate frame, introduced by Beyer Peacock at an early stage in the history of the locomotive, provides an example which may be described as midway between later British and American practice. The frames were of wrought iron, the hornblocks being forged solid with frame plates, thus entirely avoiding trouble with loose bolts or rivets andgiving a solid support to the axleboxes. American engineers adopted the bar frame which had been introduced by Stephenson in 1825, and subsequently developed
very rigid vertically.
certain amount of lateral elasticity; gives slightly on curves at speed
strong buffer beams and attachments.
stays, gussets and brackets easily attached.
deep firebox and efficient ashpan.
large coupled wheels can bc used under firebox.
good support to firebox, well above the grate.
axlebox guides and spring brackets offset
large number of bolts and rivets liable to work loose
cylinder bolts have to resist large shearing force.
Firebox inaccessible below frame for washing out.
Large number of cross stays necessary.
solid backing to axlebox guides and cheap and easily renewable shoes.
simple disposition of springs and compensating gear
f'ew bolts and no rivets to work loose.
cylinders easily fixed.
firebox accessible for washing out.
few cross stays required.
sections can bc proportioned to meet the varying stresses in different parts of the frame.
excessive lateral rigidity.
lack of vertical rigidity.
weak at front end at buffer beam and behind cylinders where bogics are used
boiler centre must be very high to allow of ample depth of firebox at tubeplate
ashpan narrow and inefficicnt.
large coupled wheels cannot he used under the wide firebox.
Conclusion. the bar frame was particiularly adaptable to American conditions of ample loading gauge and large fireboxes and grate area, while the plate type was most suitable for British requirements, except for special designs such as the engine units of the Garratt locomotive. Plate frames are the best for side tank engines, but this type is rarely used in America. .Any change from plate to bar frames, or vice versa, could not bc economically carried out. It was rather remarkable that on those railways abroad where British-built plate-framed locomotives had to compete. against American bar-framed engines, the fuel consumption was always in favour of the plate frame, which permits the use of a decp firebox and efficient ashpan.
Shields, T.H. (Paper No.194).
The steam locomotive and its future in relation to electric traction. 315-27. Disc.: 327-52; 498-501.
Presented in London by author's brother on 18 December 1925 chaired by W.A. Lelean
Includes illustration of Riekie valve gear. Considered there was a need for a locomotive which would be acapable of running over steep gradients: electric traction showed less variation. The boiler was good manager of steaming capacity. A decrease in driving wheel diameter could assist: he postulated that the diameter of the driving wheel in inches equated with the maximum speed in mph. Argued for electric traction for short distances and that the Sentinel was suitable for light traffic. An Appendix (p. 338-41) gave details of test running with 4P compounds bewteen Glasgow Central and Carlisle. (also s. el of locomotive). Discussion: J.W. Cross (328) noted that in Germany the Knorr feedwater heater suffered from choked tubes. E.A. Phillipson (328) considered that exhaust steam injectors reduced coal consumption slightly, but increased maintenance cost. Cross (328) responded by noting that all GWR locomotives were fitted with exhaust steam injectors and suffered no problems. J. Clayton (329-31) observed that the SR successfully employed.exhaust steam injectors and achieved a 3-4% reduction in coal consumption. He argued that larger boilers were more efficient and repair costs were lower. Questioned Shield's reference to smokebox superheaters: all were then of the tube type, and dampers were no longer employed. He cited the success of compounding combined with superheating on the MR/LMS. Clayton favoured the condensation/displacement lubricator.E. Graham (331-2) noted that live ssteam was used for feedwater heating in power stations as it kep the boilers cleaner. Phillipson (332) noted that top feed reduces scale formation. Sight feed lubricators needed constant watching, whereas mecanical lubricators did not. Subsequently Phillipson (335-6) noted the rapid deceleration achieved by the Westinghouse brake; furthermore, the pump used less steam than the ejector. Phillipson (342-5) contributed more in writing where he commented upon the Chingford intensive suburban service; the advantage of multiple-cylinder designs, long water legs in the firebox, the over-stated advantages of short tubes, Carnot's formula
The three chief objections to early cut-offs raised by the late cut-off exponents, and the methods by which they may he surmounted are:
(1) Excessive cylinder condensation. May be minimised by adopting high piston speeds; these are not detrimental, provided that care be exercised in the design of the reciprocating parts, and alloy steels being employed, in order to reduce weight.
(2) Excessive wire drawing. May be obviated by using long stroke piston valves or preferably poppet valves, whereby back pressure is at the same time reduced.
(3) Greater fluctuation in torque. While there is admittedly a greater pressure-range per stroke, and a somewhat lower m.e.p., the effects on the final turning moment 'diagram are largely neutralised by the use of three or four cylinders.
Incidentally, the importance of the big end bearing pressure per unit area is somewhat overrated; the problem resolves itself into one of finding more suitable white metal mixtures. Considerable economies are of course effected by res,tricting the maximum cut-off to 50-60 per cent.
The advantages of using poppet valves are to a large extent nullified when used in conjunction with ordinary radial or link gears, the inherent faults of which are still reproduced in the steam distribution. Some arrangement, such as differential cams, giving infinite variation of all valve events, provision being made for the cancellation of the effects, of the rise and fall of the engine on the springs, is preferable.
'I'here are two methods of increasing the acceleration of existing engines operating purely suburban services : Firstly, assuming that the adhesion factor is sufficiently large to make it feasible, by increasing the area of the pilot, or first port of the regulator. Secondly, by increasing the lead of the valves. This latter method, however, is not an unmixed hlcssing, and should the engine be requircd to run subsequently on other servces, involving higher peak speeds choking would occur. .
Holcroft. H. (Paper No. 195)
Steam heating of trains 354-80. Disc.: 381-405.
Presented in London on 28 January 1926 chaired by Reid
Steam as a heating medium for trains possessed several advantages. In comparison with a water circulation of equal heating effect its weight is negligible. The piping and apparatus are likewise of lesser weight and size, and a unit of steam carries a considerable amount of heat, due to the latent heat given up in the condensation of steam into water.
Certain freight trains for the carriage of perishables were steam heated including banana specials on the Great Western Railway. The vacuum-braked covered vans were insulated and fitted with steam pipes: the train pipe, instead of passing under the floor, was carried up to the ends, where the bare pipe traversed the area under the roof before descending at the opposite end. This arrangemcnt warmed the air enough to prevent damage to the fruit by too low a temperature.
Temperature of steam varies with its pressure, but no great advantages are secured by a high pressure, as the additional heating is small in comparison With the latent heat available; also the pressure is limited by the strength of the flexible hose connections and the need to safeguard.passengers and operating staff. It had heen found by experience that a maximum of 50 or 60 psi was the highest desirablc. The warming. of trains, athough not necessitating any additional labour cost at its source, was not acconiplishecl without some extra work thrown upon the locomotive boiler. In the first place, the weight ol the trains is increased by the apparatus carried, and which during six or seven months of the year is not operated, just as 1ighting equipment has to be carried in the daylight hours when out of use, its so much dead haulage.
Discussion R.W. Reid (381-3).considered that what Holcroft advocated would not cope with severe Scottish conditions. Refered to Plenum system and noted that the Wolverton system was only applied to former LNWR rolling stock. T. Barty (Wolverhampton 383-7) quoted an anecdote about frozen passengers travelling on a Southampton train; also critical of Wolverhampton system. E.D. Trask (394) made observations about the ground main systems employed at London termini.
Journal No. 75 (May-July 1926)
Swiss railway electrification. 410-18. 6 illus.
This paper which did not receive a Paper number is an abstract: Traced the development of the Swiss Railway system and indicated its importance in international communications. Early electrifications, included that of the Burgdort-Thun Railway, the experimental line between Seebach and Wettingen, and, at a later date, the more comprehensive electrification of the Simplon and Loetschberg lines. Factors having an important influence on the electrificziion schemes of the Federal Government are the dependence of Switzerland on external sources for its coal supply, and, on the other hand, the abundance of water power.
Geer, H.E. (Paper No. 196)
Modern locomotive superheating. Part 1. 419-41. Disc.: 441-50.
Presented in Leeds on 22 January 1926 chaired by Kidd
Author worked for Superheater Co. In Great Britain in 1925 only 7000 superheated locomotives, out of a total stock of 24,500. This part is concerned about demands placed upon piston valves and diagrams show Hughes' ball relief valves (Fig. 5); J.G. Robinson's compression release rings (Fig. 6); Beames' Trick ports (Fig. 7) and J.W.D. blast pipe valves (Fig. 9). Discussion H. Broscombe (442-6) discussing carbonization in piston valves: Noted that NER S3 4-6-0 No. 931 was fitted with patent rings supplied by ABC Coupler & Engineering Co. and these were claimed to lower friction; also noted the importance of running on the valve gear rather than on regulator to obviate wire drawing. G.F. Horne (446-7) spoke about the Hughes 4-6-0 and superheated 0-6-0 designs; leakage from superheater tubes and that Hughes type piston valves were fairly satisfactory, but after 20,000 miles it was necssary to remove carbon.
Pressed steel in railway rolling stock. 459-61.
Presented in Leeds on 19 February 1926 chaired by Kidd: paper did not receive a Paper number
Thorrowgood, W.J. (Paper No. 197)
Signalling from a driver's point of view. 463-85. Disc.: 485-97. 18 illus., 1 diagr.
Presented in London on 26 February 1926 chaired by H. Kelway Bamber
Mainly three and four colour light signalling on the Southern Railway. The principal advantages were:-
same aspect is displayed both day and night.
definite: no question of drooping arms when an aspect is exhibited
smaller size: they can be brought down to a position in a line with the drivers eyes
no moving mechanism: drivers always see the aspects only.
track is kept clear of signal wires.
economy in maintenance.
aspects are brilliantly displayed
no red or stop light has to be passed.
Noble, E.C. (Paper No. 198)
Ferry steamers and Garratt locomotives in use on the Entre Rios and North-Eastern Argentine Railways. 503-24. Disc.: 524-32.
Read on 19 March, 1926 at Ibicuy
The case for a Garratt trial included:
its low internal resistance through its flexibility and its high pressure form as against the compound form of the Mallet, the Garratt could develop its full tractive effort, as conclusively proved in South African railways and elsewhere. The Garratt engine in service in the works ol Vivian & Sons at Swansea showed that a Garratt with a tractive effort of 24,600 lbs hauled a 33%. heavier load than two saddle tank engines, with a combined tractive effort of 25,600 lbs (See Rly Gaz. 13 January 1924.) A further example given in the Railway Gazette 8 June 1923, noted that the Garratt hauls a load which is a greater percentage increase over the load hauled by the ordinary engines than its percentage increase of tractive cfiort is over that of the ordinary engine.
Bell, A.M. (Paper No. 199)
Automatic mechanical couplers for railway rolling stock. 540-74. Disc.: 574-86.
Presented in London on 25 March 1926 chaired by R.W. Reid
Review. W.F. Pettigrew (577-8); G.M. Rickards (LNER 582) commented upon LNER experience with automatic couplers with Pullman vestibules and stated that passengers were not subject to shocks.
Grime, T. (Paper
Steam locomotive performance (theoretical and actual). 588-618. Disc.: 619-52.
Presented in London on 29 April 1926 chaired by H. Kelway Bamber
On the theoretical side included compounding, the Uniflow (called Uniflaw in paper) cylinder system and an analysis of "Castle" tests. Discussion: J. Clayton (620-1) states that Churchward was responsible for introducing long travel valves to Britain. Dendy Marshall (623-4) advocated compounding; H. Holcroft (627-30) considered the difficulty of compounding in Britain due to restriction on cylinder size; advocated long lap valves rather than long travel valves; high boiler pressures did not lead to higher temperatures. J.W. Hobson (R&W Hawthorn, written commuinication 638-40) described work on three-cylinder tank engines for Argentina.. John Riekie (640-2) made observations on compounding. .
Journal No. 76 (August-October 1926)
Nigerian Railwaay: new 2-8-2 type freight engine. 658-61.
Illus., diagr. (s. & f. els.)
Five built by Vulcan Foundry under supervision of the Crown Agents for the Colonies; designed to the requirements of T.B. Otway Ruthven, the late Chief Mechanical Engineer, were notable for having. three cylinders and a large boiler, although the rail gauge is only 3ft. 6in. The Belpaire firebox was copper and had a combustion chamber. Two sets of Walschaerts valve gear operated the outside piston valves, while the valve of the inside cylinder was operated by rocking levers.
Warden, Henry (Paper No. 201)
Physical testing of iron and steel for commercial purposes. 675-94. Disc.: 694-700.
Presented in Glasgow on 18 February 1926 chaired by D.C. Urie
Listed incorrectly on IMechE electronic database as "Urie" and Warden: D.C. Urie chaired the meeting. Discussion: E.G. Copestake (LMS, St Rollox Works, 694) considered that the cost of sample preparartion was justified by the superior performance of the Izod impact test; R.A. Thom (695-6) was critical of the implied assertion made within the paper that the Izod impact test was only used for Government-based work as several railway companies employed the test. D. Dobbie (LMS, Inverness, 698-9) claimed experience of locomotive boiler repairs, extending over a good many years: most trouble was experienced along the legs of the back and front boiler covering plates surrounding the firebox (the steel plates of barrel and boiler wrapper plates, but ignoring the copper firebox). These back and front plates in addition to being blocked and flanged, had numerous, rivet holes bored, drifted and riveted up to enable a good fit being made of the plates where the boiler barrel joined the firebox outer plates. It was around these parts inside and outside of water spaces that most fractures developed, which required patching from time to time. During the life of a locomotive boiler, say, 35 years, it may have worn out two fireboxes, and considering the fluctuations in temperature to which it had been subjected and the treatment it received whilst in service, the participant queried whether the tests mentioned were sufficient to cover steel plates working under such conditions. Engines regularly washed out at running sheds developed distinct markings along the inside of wrapper plates directly abomve the foundation rings near the mud plug holes where the washer-out regularly plied his cleaning rod. These markings could only be detected when the boiler came to workshops for a new firebox. In an old boiler they were occasionally so pronounced that there was a real difficulty in knowing how to deal with plates so affected. Boilers with higher pressures would lead to the adoption of thicker boiler plates. Fortunately, fractures and defects of this nature develop slowly until the warning leakage is duly noted, so there is not much danger of boiler casualties arising.
Robertson, James A. (Paper No. 202)
Spark prevention devices on locomotives. 703-21. Disc. 722-6.
Presented in Santa Fe on 19 June 1926 chaired by
Mainly as applied in South America, but Fig. 3 shows a Caledonian Railway spark arrester.
Description of an eight-coupled turbine locomotive (Ljungstrom system) for
the Argentine State Railways. 727-37. illus., diagrs.
Detailed description of turbine, its condensing system, and the feed water arrangements, and its fan driven draughting arrangement.
Report upon trials of Ljungstrom locomotive. 738-40.
Water economy was being sought and tests were conducted in an arid region. The time occupied during the run on the first trial totalled 30 hrs. 40 mins., the actual running time being 23 hrs. 20 mins. The load hauled equalled 741,304 ton kilometres, with a consumption of 7,700 litres of fuel oil and 6,100 litres of water, which gives a consumption of 10.4 litres of petroleum per 1,000 ton-kilometres. 7-10
In the second trial, which took place on June 13th over a distance of 739 kilometres, the total load hauled was 733,820 ton-kilometres in 38 hrs., with 21 hrs. 25 mins. actual running time. The consumption equalled 8,750 litres of petroleum and 7,000 litres of water, which corresponds to 11.9 litres of petroleum per 1,000 ton-kilometres..
Tritton, Sir Seymour B. (Presidential Address)
Advice to your engineers. proposed subjects for papers. 743-59.
Visit to Crewe Works, 22nd July, 1926. 760
Between thirty and forty members of the Manchester Centre paid a visit to the LMS Locomotive Works, Crewe: parties were conducted round the works by Mr. Beames, his assistant, Mr. Lemon, and others of the staff. Members had an opportunity of seeing the new erecting shop, which was nearing completion. Great interest was taken in a four-cylinder unit fitted with the Caprotti valve gear on the tappet valve principle, in connection with which tests were to be carried out.
Sedgfield, P. and Forrest F.W.A. (Paper No.
Illumination of railway rolling stock by electricity. 850-78. Disc.: 878-91.
Methods available in the Argentine:
Storage batteries under each coach without dynamo.
Storage batteries to light various coaches in parallel, without dynamo.
Storage batteries with generator in the brake van to light the coaches forming the train in parallel, driven either direct from the axle or by oil or petrol engine.
Storage batteries under each coach with turbine-driven generator on the locomotive.
Turbine-driven generator on the locomotive without any storage batteries.
Storage batteries under each coach with generator slung on the bogie of the coach, making a complete lighting unit for each coach.
Same as above but with generator slung from the underframe of the coach.
Journal No. 77 (November-December 1926)
Shawcross, G.N. (Paper No. 204)
Locomotive built-up cranks. 892-905. Disc.: 905-18.
Paper presented in Manchester on 26 February 1926 chaired by W. Rowland.
The stresses which reacted most unfavourably upon built-up cranks were
Stress caused by the bending moment due to the weight of the engine, causing opening and shutting of the webs or breathing to occur during every revolution which the crank makes. This breathing action will be a varying quantity, according as the driving wheel is momentarily in a depression or striking a peak.
Stress due to the twisting moment set up by slipping of wheels when engine is negotiating a curve.
Stress due to thc bending moment produced by the rolling or oscillation of the engine causing the flanges of the wheels to strike a rail, thereby imposing a bending moment on the crank, proportional to the radius of the driving wheel.
Robinson, C.H. (Paper No. 205)
Debatable features in the design of some locomotive details. 919-35. Disc.: 935-43; 1927, 17, 346-54. illus., 10 diagrs.
Paper presented in Glasgow on 28 October 1926 chaired by D.C. Urie.
Considered pistons with bull rings, with and without tail rods and tail rod guides. The one-piece piston and rod of nickel-chrome steel as fitted to LNER 4-6-2 type engines is very light, and the reciprocating weights are reduced to a minimum, but its original cost is very much higher than the ordinary type of piston and rod due to expensive materials, extra machining operations, heat treatment, etc. The box type piston, with centre of steel casting with bull ring cast on, had been adopted as standard by the Indian State Railways. The production costs are again higher than those for ordinary types, due to machining the periphery of the steel centre to take the bull ring, and the extra cost of casting on the ring. The vexed question is, are tail rods and guides of any use?
The main features of plate and bar frames were compared. Plate were deep and flexible laterally, whilst bar were shallow with lateral strength whilst flexible in vertical plane. Staying plate frames is achieved by vertical and horizontal castings or flanged plates, secured by bolts and rivets. Bar frames relied mainly on boiler, to which they were connected by semi flexible stays at various points They were stayed by forged bars horizontally. Mountings, such as spring and brake carriers were attached by bolts or rivets to plate frames and via pins with collars put through the bar frame and secured by nuts. Spring gear was almost invariably under-hung on plate frames, whilst was almost invariably overhead on bar frames.
Reversing shafts could be: solid forged from steel billet; built-up from mild steel; smithed from Yorkshire iron, with levers welded on (by then obsolete); and steel casting (the last only being used for brake shafts at the time). Firebox foundation rings were forged from rectangular bars in Britain. In North America steel castings were used. Figure 5 showed a complex foundation ring manufactured from a mixture of cast and forged components. Five different methods of manufacturing smokebox saddles were considered, particularly in relation to differences in machining time.
Discussion: D.C. Urie chaired the meeting and opened the discussion (935-6) the idea behind piston tail rods was that of a floating piston, but experience had shown that the piston had the dual task of carrying not only its own mass, but that of the tail rod as well.
R.A. Thom (936-7) stated that when Schmidt superheaters had been introduced it had been mandated that tail rods were fitted. On the GCR it was found that tail rods led to wear in the centre of the cylinder barrels, and they were removed. A large number ol cast iron piston heads fractured, and piston heads made of hammered iron were substituted, but after a time showed signs of fracture, and as a result, cast steel piston heads were tried. It was found that these scored the bottom of the cylinder barrels, and mild steel piston heads were then fitted, with very satisfactory results. Bronze bull rings fitted to the nickel-chromium piston heads on the LNER I'acifics have proved very satisfactory. As regards the merits of bar frames compared with steel frames, the Author had evidently overlooked that the Great Central Railway had also imported twenty Baldwin locomotives. These were fitted with, bar frames, and a grcat deal more trouble was experienced with them than uith plate franics, as the bottom web of the bar frame adjoining the horn plates tended to break. At that time, there was no electric or oxy-acetylene appliances in use and the frame had to be taken down and welded in the smithy, which was a very costly operation. These engines proved so unsuitable for English requirements, that it was decided to scrap the lot after they hnd been in service for fifteen years. He could not agree that a built-up reversing shaft or brake shaft was not as reliable as a solid forged shaft. Casehardening the eyes of reversing shafts, motion details and brake shaltshad been displaced by bushing: it had been found that bushes are much more satisfactory, and repairs can be dealt with more readily. Bronze bushes were better than steel.
Irvine Kempt (LMS, 937-9) advocated the retention of tail rods until they had been fully evaluated. He noted that the circular bush could not be properly lubricated, and led to excessive wear. The cylindrical casing which surrounded the tail rods practically became a pump blowing out any lubricant to the bush. If the tail rod bushes are not kept properly adjusted, the piston rests on the bottom of the cylindcr, and the additional weight of the tail rod being carried made conditions worse. Experiencc with shrunk-on levers on shafts was limited to old Caledonian Railivay tender brake shafts. When they got loose thc shafts were sent to the smithy for the levers to be shrunk on again, and new set screws and keys were fitted: a crude method.
E.W. Selby (939-40) could not understand why many British railways retained the horseshoe front tubeplate bearing on the cylinders, instead of using a circular smokebox. With this latter type, resting on a saddle, it was possible to fit one type of boiler onto several classes of engine. The GWR had used the circular smokebox with saddle on all new and rebuilt engines since 1908. It makes a better job, and simplifies manufacture, if the top of the inside cylinders is machined to a simple rectangle forming the base for a steel saddle: steel is less liable to fracture, and saves complicated machining, An alternative was to have two very much smaller steel castings to form the ends, and to use two bent plates to form the sides: a simple, cheap and strong arrangement.
W. Williamson (LNER, Cowlairs, 940) stated that cast steel piston heads, with cast iron rings supporting them in the cylinder, gave very good results. Dismissed tail rods and argued for simplicity. The keys on reversing shafts with levers shrunk on tended to become slack. A forged shaft was much better than a built-up shaft.
A. Hallam (LMS, St. Rollox, 940) had not found piston tail rods to be satisfactory. Shafts of the solid type were preferrred as considerable trouble was experienced with built-up shafts due to the various components hecoming loose.
In his reply (941) the Author noted that the North British Locomotive Company were compelled during WW1 to manufacture built-up crank axles, and had received no complaints of loose pins, due entirely to the great care taken in finding the essential shrinkage allowances, and to the production of first class pins and holes.
Bond, R.C. (Paper No. 206)
Braking of trains on electrically-operated railways. 945-57. Disc.: 957-80.
Paper presented in London on 28 October 1926 chaired by H. Kelway Bamber.
In conclusion, the following summary of the subjects under consideration is offered as a basis for discussion
Some boiler details. 981-1002.
Address by the Chairman of the Leeds Centre on 29 October 1926: advocated Belpaire firebox on the basis that it was easier to stay; there is greater water above the hottest part; a continuous thread on both plates, and the base of the seatings is flat. Also commented upon water space stays; tube arrangements and crown stays..
Kelway-Bamber, H. (Paper No.207)
Modern British railway express passenger engines. 1004-17. Disc.:1017-29.
Paper presented in London on 25 November 1926 chaired by C.N. Goodall.
Examines the performance of a Castle class locomotive between London and Plymouth; the comparative running of Castle and A1 classes between King's Cross and Grantham, and the Lord Nelson class, T.S. Finlayson (1027) contributed to the discusaion with some rather sharp remarks which noted the importance of firebox volume and noted that superheating increased the volume of the steam. He considered that locomotive horsepower corresponded to 50 times the grate area and therefore expected 2000 hp from the A1, 1650 from the Lord Nelson and a mere 1500 hp from the Castle