Journal of the Institution of Locomotive Engineers
Volume 19 (1929)

Steamindex home page  Updated 2017-02-17 Key file The IMechE virtual library is accessible (full papers, all diagrams, photographs, extensive tables, via SAGE

Journal No. 88

Byrne, B.R. (Paper No. 238)
Some notes of metallurgical importance in locomotive engineering. 10-38. Disc.: 38-50; 120-6.
Opening Meeting of the 1928-29 Session was held at Denison House, Vauxhall Bridge Road, London, on Thursday, 27 September 1928: J. Clayton, (Vice-president), occupying the chair.
Notes extracted from the Author’s private records. They are the fruit of exchange of opinion with colleagues and with locomotive engineers, metallurgists, steel-makers and founclrymen. Some of the ideas embodied in this Paper are not original, but have been “ absorbed ” by the Author and are so much a part of his mental equipment that their source is forgotten. No excuse need he offered for this, as it applies to us all. Nevertheless, the Author’s own observations form the bulk of the subject matter, and outside sources are quoted as little as possible. Further, no ideas are put forward which are not backed by personal experiment. The treatment is necessarily sketchy, but it strikes at essentials, the principal aim being to focus attention on the metallurgical side of locomotive building. There is a very real need for the frank and willing exchange of ideas between designers, metallurgists and the technical staff. Anybody who tries to exercise reasonably close control of raw material will find boundless scope for patient observation, and in many cases fur serious research.
Choice of materials; semi-finished steels; influence of carbon content; heat treatment, wrought iron; alloy steels, manganese brasses; alloys for firebox water-space stays (copper fireboxes); control testing of steel; Brinell hardness testing; chemical analysis; phosphorus and brittleness.
Discussion: A.C. Carr (38-40) noted that no reference was made to spring steel nor its treatment. Spring steel is probably one of the most troublesome components of locomotive and rolling stock maintenance. For instance, taking laminated spring steel, the British Standard Specification provides for 0.5 to 0.8 carbon, a very wide margin. Some of his steel friends had told him that the carbon content for water-hardening steel should be 0.53 to 0.63 and for oil-hardening 0.75 to 0.85. It appears possible under the British Standard Specification to obtain a steel which is not suitable for water-hardening. As far as he knew, in Britain all the laminated springs were water-hardened, while coil springs were generally oil-hardened.
Second Ordinary General Meeting of the Newcastle Centre (Session 1928-29) held in the Lecture Hall of the L&NER. Institute, Darlington, on Tuesday, 6 November 1928, the chair being taken by R.A. Copperthwaite (pp. 120-6): Mr. P.W. Bollen 123-4) noted the use of wrought iron by the home railways seemed to be one of the things that die hard in the locomotive department, and it is often specified as a matter of practice. On the other hand, British private builders avoided its use as much as possible, and when doing work for the railwxys were often able to obtain permission to substitute a mild steel, such as BSI class A steel: this was particularly the case with solid forged brake shafts and reversing shafts, and also for welded foundation rings for boilers.

Armstrong, J.C. (Paper No. 239).
Pulverised fuel locomotives. 53-90. Disc. : 86-114; 492-9: 1930, 20, 146-55; 325-34 + 2 folding plates. 6 illus., 17 diagrs.
Second Ordinary General Meeting of the 1928-29 Session was held on Thursday, 25 October 1928, at Denison House, Vauxhall Bridge Road, Loncbn, at 6 p.m.: R.E.L. Maunsell chaired meeting. Brief account of paper in Locomotive Mag., 1928, 34, 357.
Advantages obtained by using pulverised luel locoiuotiws claimed:

Attention was paid to fitting pulverisers to locomotive tenders. Maunsell chaired the initial meeting and made a number of Presidential comments (pp. 86-90) his conclusions being
coal in pulverised form can be burnt in a locomotive without any extensive alteration being made to the boiler or firebox.
coal of a lower quality than possible to use for grate firing, can be used in pulverised form.
economy can be effected by the purchase of small coal and slack, which is really better adapted for pulverising purposes than the large coal that is necessarily used for grate firing.
when pulverised fuel is used, boiler pressure can be better maintained, and more finely adjusted to suit varying conditions of road and load than is possible in a grate fired boiler.
Throughout the run at which he was present, the maximum variation in pressure was 71bs., which occurred when the train entered a gradient of 1 in 130, the weight of the train being 1,300 tons, and when the fuel feed was adjusted, full pressure was quickly obtained. Throughout the remainder of the run the finger of the pressure gauge practically remained steady on the point of maximum boiler pressure.
there is no spark throwing, and very little smoke when pulverised fuel is used.
the quantity of ashpan and smokebox refuse is negligible.
Sir Henry Fowler (90-2) opened the discussion with some rather penetrating comments:26 years ago, his then chief, Samuel Johnson, sent him to look at a boiler in London whicli vas fired by pulverised fuel, having in his mind the question of its adaptation for locomotive purposes. There was trouble with this boiler, owing to the fact that thc basic slag, which was formed badly, corroded the firebrick which lay in the furnace–this is a trouble with all boilers using pulverised fuel, although Armstrong has not mentioned it. In one of the boilers which he had seen in Germany using pulverised fuel, very little firebrick was used, but hr believed the difficulty had been met by arranging a very large number of burners vhich gave a short flame. One of the greatest difficulties in introducing powdered fuel in connection with electric light plants has been due to this particular point, even when some of the combustion chambers were of very large size. The difficulty experienced with a powdered fuel 1ocomotive used in America was similar and overcome by the use of very short flames.
Other particpamts to the London discussion included: H. Chambers, Clayton, Holcroft, Bulleid and Lelean. {KPJ needs expansion}
In the discussion the author (page 492) noted that The German Government were interested in pulverised fuel as they wished to use the lignite in Central Germany. The German Government said, “ If you will carry out some tests and if these tests show you can burn this fuel, we will give you an order.” The A.E.G. demonstrated with a stationary boiler that their system for burning pulverised fuel was satisfactory, and then received an order from the German Government. This firm has spent an enormous amount Pp.86-90 (19) : Maunsell adds some notes on the purchase of A.E.G. equipment for the S.R. : the paper is basically about the German results from the system. A.C. Stamer (Chairman, 146-7); R.J. Robson (147-8) experience on Atcheson Topeka and Santa Fe; S.L. Baister (148-9); P. Liddell (149-51) problems of pollution from pulverization process. 20: A.E. Kyffin (326) queried costs and structure of furnace; Carling (20, 327) suggested that a modified boiler was needed and this could be fitted on a Beyer Garratt; Loach (327); E.F. Lang (327-9); S.H. Whitelegg (329) noted problems with fuel preparation; Anderson (making reference to Carling) suggested the Garratt type
Second Ordinary General Meeting of the Newcastle Centre (Session 1929-30) held at the Central Station Hotel, Newcastle-on-Tyne, on Wednesday, the 6 November 1929, . A.C. Stamer occupying the chair.
Fifth Ordinary General Meeting of the North- Eastern Centre (Session 1928-29) held at the Hotel Metropole, Leeds, on Friday, 25 January, 1929, the chair being occupied by E. de H. Rowntree (492-9). L.W.R. Rowntree (494-6) wondered to what extent the German Government had helped or subsidised the manufacture of this experimental locomotive. There are ways in Germany of subsidising private enterprise to investigate such prob]ems as these, because the cost to a private firm is enormous, and it is obvious that the State Railways had given the A.E.G. exceptional facilities for testing out this engine on rail. With regard to the unburnt fuel which was collected, it would be interesting to know the method by which this fuel was collected. It is stated that the burners are cooled by water from the tender, and he would like to know whether a great deal of heat from the burners goes back into the tender so that the temperature of the feed water is heated to such an extent as to impair the working of the injectors. It is stated that steam is raised in 30 to 45 minutes, which seems a very short space of time. Has this been found to have any detrimental effect on the boiler or tubes
Next volume: Second Ordinary General Rleeting of the Manchester Centre (Session 1929-30) was held in the Building of the Manchester Literary and Philosophical Society, 36, George Street, Manchester, at 7 p.m., 6 December 1929: Mr. J. N. Gresham taking the chair. .

Journal No. 89

Kelway Bamber,  H. (Paper No. 240)
Modern steam rail cars in service. 143-63. Disc.: 163-70; 314-33. 2 illus., 6 diagrs., 12 tables.
First Ordinary General Meeting of the Newcastle Centre (Session 1928-29) held at the Central Hotel, Newcastle, on Tuesday, 9 October 1928: chair taken by Mr. B. Irving, Vice-chairman of the Newcastle Centre, who read a letter of apology from Mr. A.C. Stamer, the Chairman of the Centre, regretting his inability to be present at the Opening Meeting of the Session, due to his services being required in connection with the Royal Visit to Newcastle. Fifth Ordinary General Meeting of the 1928-29 Session was held at Deniwn House, Vauxhall Bridge Koad, London, on Thursday, the 31st day of January, 1929, at 6 p.m., Sir Henry Fowler, K.B.E. taking the chair. .
Includes economic as well as technical aspects. Maconachie (165-7) claimed "a lot" of failures; problems with steaming, and the need for at least a 50% increase in boiler capacity. The spur garing was very unreliable and with chain drives lubrication and cleaning were very important (KPJ: just like a mountain bike) B.H. Harper (167-8) presented information on the performance of the six-cylinder Sentinel car: its improved riding, its more accessible engine (it was even possible to take down the big ends without access to a pit) and the higher rate of acceleration. With the two-cylinder cars it was found that unit coal and oil consumption fell as mileage increased: the cars "must be kept continually in traffic". With a half-hourly Knaresborough to Harrogate service coal consumption was 12lb per mile and oil consumption two pints per hundred miles. Claimed that there were no boiler problems. Stewart (168-9) considered that chains were most appropriate for heavy haulage; at that time cardan shafts gave trouble. Bollen was critical of firegrate: enginemen could not see where coal was going. The two-cylinder version suffered from difficulties in starting...

Windle, E. (Paper No. 241)
The locomotive smokebox. 171-87. Disc.: 187-91.
Second Ordinary General Meeting of the North- Eastern Centre (Session 1928-29) held at the Hotel Metropole, Leeds, on Friday, 16 November 1928, at 7.0 p.m.: chair taken by E. de H. Rowntree.
The Macallan blastpipe and Churchward's jumper blastpipe nozzle are mentioned on p. 175. Blast pipe nozzle dimensions and gas area are considered. The design of blowers and the location of the blower valve are evaluated: the latter should enble fast operation. The effect of superheaters and steam pipes are important issues. The GWR employed coned metal-to-metal joints on its smokebox doors; elsewhere asbestos rings were used.

Anderson, D.S. (Paper No.242).
The future development of the locomotive. 193-212. Disc.: 212-21; 630-40: 1930, 20, 204-13. 3 diagrs.
Third Ordinary General Meeting of the 1928-29 Session held at Denison House, Vauxhall Bridge Road, London, on Thursday, 29 November 1928, at 6 p.m., . W.A. Lelean occupying the Chair. The Chairman said the members would regret that a message had been received from the President, R.E.L. Maunsell, that it was impossible for him to be present that night, and also a letter to similar effect from Sir Henry Fowler.
Having touched on so many points in the course of the Paper, a brief summary of the many arguments might not be out of place. The characteristics of the internal combustion engine were shown to be unsuitable for direct application to locomotive work, and in the process of adaptation it becomes overloaded with so many contrivances to minimise these unsuitabilities that the proposition loses a good deal, if not all, of its attractiveness. Retaining steam as the prime mover suggested the use of a turbine, and this had been tried with some success. A case was made out, hovever, for a condensing reciprocator with triple expansion. It was shown that, provided one worked with a moderate vacuum, which is all that might be obtainable, the volume of thc steam at exhaust conditinns could bc accommodated within reasonable cylinder ditnensions. Recent developinents in boiler practice suggest the use of a high pressure water-tube boiler with pulverised fuel firing. The engine should be fitted with some form of valve gear other than a link motion, and the condenser should be of the evaporative type. No doubt it will be argued that the complication is too great to contemplate, but what is the alternative? Any internal combustion engine will have at least six, if not eight, cylinders, and much auxiliary gear. The economy of the turbine can be easily over-estimated on such difficult work, and there is the problem of double reduction gearing. A step which is the logical development from existing conditions and which introduces the minimum of new problems is surely worth a trial.
Discussion: (Volume 20): M. Blacklock (204-6); J.B. Hobson (206-8) considered the turbine; P. Liddell (208-9), P.W. Bollen (209-10 and MacArthur (210-12) all considered diesel locomotives
Sixth Ordinary General Meeting of the Scottish Centre (1928-29 Session) held jointly with the Institution of Mechanical Engineers in the Societies' Room, Royal Technical College, Glasgow, at 7.30 p.m. on Thursday, 28 March 1929. The Chair was occupied by Mr. C.H. Robinson, Chairman of the Centre, who was accompanied on the platform by Mr. E. Bruce Ball, (Chairman of the Glasgow and West of Scotland Branch of the Institution of Mechanical Engineers). Dr. D.S. Anderson, Ph.D., B.Sc., Principal of the Technical College.

Lawrence, L.  
The Baker valve gear. 222-4.
Third Ordinary General Meeting of the 1928-29 Session was held at Denison House, Vauxhall Bridge Road, London, on Thursday, 29 November 1928, at 6 p.m., Mr. W. A. Lelean occupying the Chair.
As applied to a model locomotive by "Curly" Lawrence (Model exhibited at meeting)..

Millar, W.A. (Paper No. 243)
Locomotive cab arrangements. 225-39. Disc.: 239-47.
Second Ordinary General Meeting of the Scottish Centre (1928-29 Session) held in the Societies’ Room, Royal Technical College, Glasgow, at 7.30 .p.m. on Thursday, 9 November 1928, C.H. Robinson occupying the chair.
There had always been a difference of opinion on this subject: before the Grouping of 1923, the 16 chief railways of Great Britain were eqrially divided – eight favouring right-hand drive and eight left-hand drive. Analysing these figures it will be found that of the six companies which formed the LMS, two preferred right-hand and four left-hand drive, while the group standard is the latter, as on all recently built passenger and freight engines. The GWR has naturally maintained its previous preference for right-hand drive, while the Southern favoured the left-hand side, as on engines of the King Arthur and Lord Nelson classes–one of the old companies preferred the right-hand and two the left-hand side. On the LNER four used right-hand and two left-hand drive, until recently the standard being the former (right-hand) as found on the improved Director, Pacific and Shire classes.

Holcroft, H. (Paper No. 244)
Some points of common interest in rolling stock and permennent way. 249-84. Disc.: 285-311; 823-30. 27 diagrams
Joint Meeting with Permanent Way Institution. Fourth Ordinary General Meeting of the 1928-29 Session was held at Denison House, Vauxhall Bridge Road, London, on Thursday, 13 December, 1928, . J. Clayton, Vice-president, occupying the chair. Apologies for absence received from C.B. Collett.
Permanent way functions:
support the wheel loads and form a path;
guide the vehicles in a given path;
provide the reaction to the tractive effort, or, conversely, to the braking force.
Two-cylinder engine: Relatively large wheel blow due to primary weight. Large axle blow due to two primary weights at right angles to one another having a combined effect equal to about 13 times the wheel blow.
Four-cylinder enqine: very light wheel blow due to small secondary weight. No axle blow, as weights are at 180° apart.
Three-cylinder enqine: Relatively large wheel blow due to secondary weight, but this is about one half of that of the two-cylinder, owing to lighter reciprocating parts and a lesser proportion of them balanced. No axle blow, as weights are at 180° apart. The wheel hammer blow is of importance in relation to the track, while the axle hammer blow applies more to bridges.
The investigations of the Bridge Stress Committee of the Board of Scientific and Industrial Research have necessitated close study of the practice adopted in locoomotive balancing, and attention has been focussed on several important points. Firstly, there has been in the past great diversity of opinion and practice as to the percentage of reciprocating masses to be balanced; secondly, that the prescribed amount of balance is seldom obtained and varies in different pairs of nheels off the same pattern, owing to the wheel itself being out of balance, due to blowholes or sponginess in the balance weight crescent or part of the wheel rim. Thirdly, that the multi-cylinder engines do not stress the track and bridges to the same extent as the corresponding two-cylinder engines do. Another point to be observed is that the ratio of the masses of the reciprocating parts to the mass of the whole engine is much smaller than formerly, especially where high-tensile steels and light sections are used, so the disturbing forces have less effect upon the engine. As a result of this investigation, excessive balancing is being reduced so that it does not set up a hammer blow above an agreed maximum. New driving wheels are adjusted for balance on a machine, to ensure that they are uniform and have the prescribed amount. In new design of heavy engines reciprocating balance is reduced to a minimum, especially in multi-cylinder engines with alloy steel parts.
Discussion: most particpants were from the Permanent Way Institution.
A Devon (288) The Author speaks about the interlocking of the "fibres" between the surface of the rail and the tread of the wheel, and as the structure of steel is crystalline I do not understand what the Author means by the word "fibres."
In dealing with the action of vehicles on curves the Author says that another important consideration is that a force must be applied through the flanges of the wheels to rotate the vehicle about its radius of gyration, and I take it by that that he means a couple must be applied through the flanges of the wheels to rotate the vehicle about a vertical axis through the centre of mass. In Fig. 4 the Author speaks about the force M causing the angular acceleration of a locomotive as it entered upon a curve as being equal to the force ½°F due to centrifugal action. It seemed to me that unless the transition curve is badly arranged the force M must be very far short of the force F. With regard to having cylindrical tyres instead of coning them, it would appear from the Author's remarks that it would be advantageous to have the tyres cylindrical instead of coned, and 1 would like to know whether cylindrical tyres have ever been tried. If what the Author has stated is true-and it seems to me very sound-it would be very useful to try a pair of bogie wheels to see if they would give the results anticipated.
The Author says that good results are being obtained from bolting flat bottom rails on a concrete bed, although he has previously mentioned that rails bolted to rock gave very unsatisfactory results, and this seems rather contradictory. The heavy wear of the left leading tyre appears very surprising to me. The Author thinks it is probably due to the ballast under the outside rail of a double track not giving the same amount of support as the ballast under the inside rail. If that is the cause, then on a single track such undue wear of the left wheel will not take place. I have always been under the impression that an electric locomotive with its uniform turning moment and absence of hammer blow is an ideal machine for running on a railway, but from the remarks of Mr. Willos it would seem that the permanent way department is more concerned about the destructive action of electric locomotives on the track than the behaviour of the steam locomotive with its hammer blows.
Opening Meeting of the Newcastle Centre (1929-30 Session) held at the Central Station Hotel, Newcastle-on-Tyne, on Tuesday, 8 October 1929, at 6.30 p.m. In the unavoidable absence of Mr. A.C. Stamer, the Chairman of the Centre, Mr. M. Blacklock presided. . C. Schlegel: Anything which goes towards maintaining an engine in traffic is welcomed by running sheds, as it is a serious matter when an engine has to be stopped for the wheels to be talmi eut for flanges to be ttirnecl up. For this reason 1 was interested to note the American contour of tyre shown in Fig. 12, which appears to me to be less liable to flange wear and somewhat resembles the contour of tyre on our Pacific engines on the L.N.E.R. These engines are: working daily between Edinburgh and York, and there are a good many curves, especially on the North Section, but we are not troubled with flange wear, and these engincs are completing over 100,000 miles between shop repair. The Author has referred to the wear on the left leading flange of the 0-6-0 type, and I can bear out what he has said, but consider this is chiefly due to engines working in one direction over a section of the line running round curves and getting wear mostly on that side. I should !ike to ask the Author for his explanation o f what we call a roaring rail and the hard abrasions one notices at equal spaces along the bull head of the rail.

Summer Meeting in Germany, 1928. 336-453
The 1928 Summer :vleeting of the Institution was held in Germany, about 100 members being present. By the courtesy of the principal officials of the German State Rlys. of their London representative, Herr Otto Mann, and of several locomotive and rolling stock manufacturers, the following programme was arranged:-
Programme of events.
Saturday, 9 June. Departure from London for Hook of Holland.
Sunday, 10 June.
Arrival at Cologne.
Trip on River Rhine to Konigswinter.
Monday 11 June
Visits to Thyssen Steel Works at Mülheim, and Wagon Fabrik A.G. at Uerdingen; or, alternatively,
Visit to State Railway Works at Schwerte.
Tuesday 12 June.
Departure from Cologne for Cassel. Visit to State Railway Works. Automobile Excursion to Mündcn, by invitation of Messrs. Scbmidt'sche Heissdampf GesmbH.
Wednesday·13 June
Visit to Messrs. Henschel and Sohn's Works.
Automobile Excursion to Wilhelrnshohe and Lunch at Schloss Hotel, by invitation of Messrs. Henschcl and Sohn.
Dinner at Hotel Schirmer, by invitation of Messrs. Schmidt'scbc Heissdarnpf Ges.mbH.
Departure by night train for Berlin.
Thursday 14 June
Visit to A.E.G. Works at Henningsdorf.
Visit to Klingenberg Power Station.
Institution Dinner at Rhinegold Restaurant, Berlin.
Friday 15 June
Visit to State Railway Testing Plant at Grünewald.
Visit to Charlottenberg Technical Academy or, alternatively,
Dynamometer car trip to Belzig with pulverised fuel fired locomotive
German State Railway Dinner to Members of Institution at Hotel Kaiserhof, Berlin
Saturday, 16 June. Departure from Berlin to London
Sunday, 17 June.
Arrival in London

Wednesday·13 June: Visit to the Works of Messrs. Henschel and Sohn, Cassel. 383-405
Locomotive with turbine tender (388)

Journal No. 90

Devlin, S.R. (Paper No. 245).
The Clayton steam rail car. 456-75. Disc.: 475.91. 3 illus., 11 diagrs.
Second Ordinary General Meeting of the North Eastern Centre held in the LNER Mechanics Institute, Doncaster, at 7 p.m. on Friday, 2 November, 1928, . G.A. Musgrave taking chair.
Clewer (page 476) asked if oil firing could be used and was told the boiler was particularly suitable as a refractory lined combustion chamber is fitted to the bottom of the boiler in place of the firegrate and ashpan, and the burner is fitted in the bottom and in the centre of this cylindrica1 chamber. Starting was performed by a small auxiliary burner and hand pump.

Robson, T. (Paper No. 246)
Experiments on buffer springs—their shock-absorbing capacity. 500-29. Disc.: 530-2.
Third Ordinary General Meeting of the Newcastle Centre (Session 1928-29) held at the LNER. Institute, Darlington, on Tuesday, 5 February 1929: chair taken by Mr. A.C. Stainer. Seventh Ordinary General Meeting of the North- Eastern Centre held at the Hotel Metropole, Leeds, on Friday, 22 March, 1929, at 7 p.m., the chair being taken by Mr. E. de H. Rowntree.

Taylor, G.H. (Paper No. 247)
Reduction of weight in rolling stock. 533-60. Disc.: 560-8.
Sixth Ordinary General Meeting of the North-Eastern Centre (Session 1928-29) held in the Hotel Metropole, Leeds, on Friday, 22 February 1929: chair occupied by E. de H. Rowntree. A large number of specimens of manufactured aluminium, suitable for use in railway carriages and motor cars, were exhibited, and these included castings, rolled and extruded sections, drop forgings, rolled sheets, bolts, nuts and nails, which were all loaned by the Aluminium Co. Ltd., of London.

Bulleid, O.V.S. (Paper No. 248).
Poppet valves on locomotives. 569-605. Disc. 605-23 + 9 folding plates. 9 illus., 29 diagrs., 3 tables.
Sixth Ordinary General Meeting of the 1928-29 Session held at Denison House, Vauxhall Bridge Road, London, on Thursday, 28 February 1929: the President-Elect, J.R. Bazin, occupying the Chair.
Paper dealt with poppet valves of the Lentz system, which is the type with which the LNER had the greatest experience. There were two distinct types of Lentz poppet valve gears:
Direct drive type and Intermediate type. The initial applications were to an inside cylinder former GER 0-6-0 No. 8280 and to GER 1500 class 4-4-0s (B12) and to the three-cylinder D49 Shire class. In the discussion A. Caprotti (pp. 605-14) described his system with illustrations of its application to an outsside cylinder 0-6-2T, and its actual valves, and disgrams of indicated horse power. Signor Caprotti : The masiiiium temperature I have observed has been about 35O°C.; that was on a locomotive in Sardinia with valves of 110 mm. diameter. I have also noticed this temperature in America when testing a locomotive of the Baltimore and Ohio R.R. There has been no trouble in thc working of the valves, when made of chronic-nickel steel. In one case a contractor manufactured the valves \vith unsuitable steel, and in that instance there \wre failures due to the bad qiiality of the steel. So troublc is experienced with the right steel, well worked
H. Chambers (618-19): wished to ask the Author whether, with the application of very high pressures and the increased temperatures that are likely to he consitlered in the future in the locomotive world, the poppet gear will withstand distortion, this I think that is one of the critical points that will have to be consitlered. Generdly speaking, the poppet gear used by both Lentz arid Caprotti systems has stood up very well. There have been cases of failure; one ran hardly cxpect a \.nl\.e to stand up without any failures ; but generally speaking the results have been extremely good. I have taken the opportunity of examining some of the valves exhibited by Mr. Bulleid, which have been taken out after three years' service; one of them shows distinct .signs that it has not been seating as it should have done, but the others are quite good. Witli the high temperature steam which may have to be considercd, what will the effect be? If Signor Caprotti can Rile us my information on that matter, it will he most interesting.' Mr. Bullcid mentioned the growth of carbonisation round the outside seat of the valve, but I should have thought that the application of the air valves which are fitted on Mr. Gresley's engines and also the very efficient by-pass arrangement which the poppet valve affords would have reduced that carbonisation to practically nothing. The fact that it is there is most disturbing; it may be that it is due to over-supply of lubrication. In another case a valve seat exhibited shows the results of a hammering action. It would he interesting to know why that has taken place in view of the acrion of the valve being under the control of the cam until just before the point of the valve seating, as Bulleid described so minutely. Caprotti replied that the maximum temperature observed had been 350°C in Sardinia with valves of 110 mm diameter and in America on the Baltimore & Ohio RR.
A. Devon: (619) In order to obtain the maximum economy in steam consumption it is necessary to compress the steam in the clearance space up to a pressure equal to that of the admission steam. If the compression is sufficient to do that for a late cut-off or low speed, then, because at high speed the back pressure is generally much higher than it is at low speed, one ought to have less cornpression at an early cut-off or high speed than at a late cut-off or low speed; but I understand that on the L, N. E. R. locomotive the cornpression is actually less at late cut-off than it is at early cut-off. Signor Caprotti has also mentioned that in the United States he has had to reduce the compression at late cut-off. Is that done merely to get a larger tliagram without any consideration for economy in steam consumption? If the compression is correct for early cut-offs, it should he really made greater for late rut-offs in ctrdcr to ohinin the highest economy in steam consumption. 'I'he value of compression lies solely in its ability to eliniinatc the waste of stteam that would take place owing to clearance if there were no compression. Compression is not requirctl for any cushioning effect, for if a locomotive can run smoothly without cushioning when drifting at high speed, it can do so also when the throttle is open. With reference to the indicator diagrams that have been shoum it appears to me that the lengths of the indicator diagrams at high speed are g r e a t e r than the lengths of the indicator diagrams at low speed. That is a fault which is due to the over-running of the indicator drum at high speed owing to inertia; it is a fault very difficult to eliminate, but unless it is eliminated the diagrams must necessarily be badly distorted.
Newcastle meeting chaired J.W. Hobson
J C. Stopani Stuart: (Communication: 621 et seq) Steam distribution by means of poppet valves is a subject in which the railway world is at present greatly interested. Bulleid is, therefore, to be congratulated upon’ having produced bis Paper at such an opportune moment and affording the members of the Institution an opportunity of discussing this very specialised branch of the industry.
Poppet, or double beat, valves are in themselves not new, but their application to locomotives in this Country is comparatively ncw, so that inforination as to thcir behaviour under working conditions is practically nonexistent. the \Vriter, with others, looks forward to another paper from Mr. Bulleid, giving a comparison between the Lcntz valve gear and the Caprotti valve gear now being built by Messrs. Wm. Beardmore & Co., of Dalrnuir.
In perusing the Paper, several points of interest to the Writer have emerged. Reference is made to the original type of Lentz gear and to its well known limitations. The It'riter would be pleased to learn what is the average gain in efficiency of this type. It would then be possible to separate that gain from the total gain of the rotary type gear and poppet valves, thus providing useful data for consideration on conversion jobs. It is stated that the valves seat themselves nhile still in contact with the rollers, as on Caprotti gear. Can hlr. Bulleid say what clearance is normally allowed between the valve stems and rollers, and what the limits arc to which they may be safely adjusted without preventing the valve seating itself. Is it to be understood that only on high-powered engines with large cylinders does this gear give satisfaction?
Having to lubricate the valve spindles on horizontal valves is one argument in favour o f vertical valves, which do not require any lubricant other than condensed steam. The cost of the oil may be slight, but it is, nevertheless, there to be added to the other objections to horizontal va 1 ves .
Reference is made to the valves; the Lentz design is well known, wherein the mild steel valves seat themselves on narrow, flat faces. These features have interested the Writer for a number of reasons. Poppet valves have been used for many years on stationary uniflow engines, wherein the majority are of special design, having the top face flat and the bottom face of conical shape, and are usually seated on some form of flexible sprrng seating. On the Caprotti valve gear similar facings to those just described are used, and the valves and cages are made of nickel-chrome steel and go through an elaborate oilhardening process to prevent distortion in use. It would be interesting to have hfr. Rulleid's comments on these points and to learn if he has ever tested .for " truth " a Lentz valve after it has been subjected to loog use under superheated steam ?
It would appear from the information given that the rotary cam profile is " stepped," giving a certain definite number (only) of predetermined " cut-offs." This feature tloes not compare fa\rourably with a Caprotti gear, which gives an infinite range of " cut-offs " but has constant lead. According to a certain school of thought, whose c-ontentions are in some instances borne out in practice, constant lead should be maintained for all '' cut-offs." The Writer does not agree with this himself, and thinks the Lentz variable lead a valuable feature, it being analagous to advancing or retarding the spark in a petrol engine. With regard to the reversing shaft which runs the width of the vehicle, can Mr. Bulleid say if cylinder expansion, frame distortion, or vibration, has affected this part in any way. Also will he give particulars of the steel and its treatment, used for cams, rollers, etc. Reference is made to the time taken to inspect a set of poppet valves--g hours. The Caprotti gear can be inspected in about as many minutes, as the boxes are clamped and can be easily slid out of position, while four nuts hold each valve in place. The combined valve seating and cage is a good feature, since oiled-up valves can be easily withdrawn and they do not cause the trouble that the Lentz type does.
It is interesting to learn that the L. & N.E. Railway have had instances of piston salves giving economies greater than poppet valves. This has happened on other railways, and points to the need of closer observation on tests and careful analysis of the conditions of running, for obviously poppet valves ought to give improved results over piston valves. Can Mr. Bulleid account for the large difference in the results obtained from the comparative engines ?

Journal No. 91

Southgate. F.D. (Paper No. 249)
Running and maintenance of Garratt locomotives. 681-92. Disc.: 692-703.
Third Ordinary General Meeting of South American Centre held on board the ferry-boat Delfina Mitre between Campana and Ibicuy, on Saturday, 22 September, 1928, Mr. E.C. Noble occupying the chair.

Law, W. (Paper No. 250)
Locomotive boiler defects and their repairs. 710-24.
Third Ordinary General Meeting of the Scottish Centre (1928-29 Session) held in the Royal Technical College, Glasgow, on Thursday, 13 December 1928, at 7.30 p.m. Mr. C.H. Robinson, Chairman of the Scottish Centre, presided,
Corrosion internal and external, but more especially internal, is the malady from which most locomotive boilers suffer. Internal corrosion presents itself in various forms, each having a character of its own, but only sometimes strongly marked. These are usually designated as :
(1) Uniform corrosion, or wasting away ;
(2) Pitting, or honeycombing; and
(3) Grooving.
It has been said that the first is caused by the chemical action of the feed-water or substances introduced into the boiler; the second by the chemical agents assisted by galvanic action, and the third by chemical and mechanical action combined. By uniform corrosion is meant the wasting away of the plates where the water corrodes them in a more or less even manner in patches of considerable extent. The presence of this, as well as other kinds of corrosion, although covered with a considerable thickness of scale, is very often revealed on emptying the boiler by the “bleeding,” or red streaks where the scale is cracked. Uniform corrosion may in some cases be found where the plates are entirely free from scale, and in consequence of the even surface of the plate and the absence of any well defined limit as to its extent, it may easily escape detection.

Roosen, R. (Paper No. 251)
Pulverised fuel burning in locomotives. 725-52. Disc.: 752-63.
Fifth Ordinary General hleeting of the Scottish Centre (Session 1928-29) held in the Societies’ Room, Royal Technical College, Glasgow, at 7.30 p.m., on Thursday, 14 March 1929, the Chairman of the Scottish Centre, Mr. C.H. Robinson, presiding.
Investigations and results of trials by Henschel of Cassel, on pulverised fuel. Describes research on creating suitable pulverised fuel burning equipment for locomotives

Journal No. 92.

Crook, G.H. (Paper No. 252)
Route and speed signalling. 770-805. Disc.: 805-22.
Seventh Ordinnry Genera1 Mceting held at Denison House, Vauxhall Bridge Road, London, on Thursday, 25 April 1929, after the Annual General Meeting. The chair was taken by the President, . R.E.L. Maunsell. Author was of the GWR Signalling Department, Reading.
Speed-signalling conveys its message to the engineman directly in terms of speed. Route information is generally considered to be unnecessary, but can be given as auxiliary information by means of route indicators. It aims at standardising the indications conveyed to the driver so that the same indication means thc same thing wherever it is displayed. 'I'hc basic aspects are simple and should be capable of being learned by a person of average intelligence in one hour, and if the underlying principles are thoroughly grasped should be permanently remembered after a little practice or reflection. At complicated junctions less signals are necessary and these can be kept more intimately in sight of the driver, an important advantage in foggy weather. One mast only per track signalled is required, and its unmistakable application to that particular track can be better securcd than in the case of the route system. Transitional speed indications, as well as definite speed indications, come within its code, that is change from one speed to another, and these transitions should be of almost equal usefulness to the indications of definite speeds, and in addition they should form a valuahle contribution to the solution of the problem of the operation of distant signals in short sections. The ideal block system is one allowing following movements at equally timed short intervals—compared with the stream of petrol-driven traffic on a public roadway—and the speed-signalling system promises a much closer approximation to this ideal than does the route system.
Finally, automatic train control systems are from various causes (disastrous and otherwise) gradually establishing their claim to development and inclusion as components of our visual signalling systems, and the fact should be appreciated that, unlike the driver, the automatic train control systems can only "think" in terms of speed. The application of automatic train control (speed control) tends to bring to light many peculiarities in our existing route signalling systems and, with a clearer conception of speed and braking characteristics, there are possibly some things we might do better in the two-aspect route system.
It is certain that the introduction of some such system of speed-signalling aspects would clarify the interpretative work of the drivcr, simplify manipulation by signalmen and increase train capacity of existing lines.