August 4, 1910J 



NATURE 



155 



on Friday evening. The many excursions and visits to 

 works were attended by large numbers of members of both 

 societies and their lady friends. 



.At Birmingham, four papers on the handling of loco- 

 motives at terminals and running-shed practice were con- 

 tributed by Messrs. F. H. Clark, F. M. Whyte, H. H. 

 Vaughan, and \V. Forsyth, all members of the American 

 Society, and one on the same subject by Mr. Cecil W. 

 Paget, member of the British Institution and general 

 .superintendent of the Midland Railway. 



In the latter paper, Mr. Paget gives plans and descrip- 

 tion of two of the most recent sheds built in this country, 

 viz. the Great Western sheds at Old Oak Common, of the 

 centre turntable or round-house type, and the London and 

 South-Western shed at Eastleigh, of the through straight 

 type. Straight sheds are economical in first cost and main- 

 tenance, but unless they are of the type known as 

 "through sheds" they are aw^kward to work; the latter 

 class are necessarily draughty. The centre turntable type, 

 though more expensive to build, possesses considerable 

 advantages of working, because engines can be easily got 

 in and out without moving others, and, in addition, better 

 lighting and convenience in getting about and in bench 

 accommodation are possible. There is, however, the dis- 

 advantage that when the turntable requires lifting for 

 repairs it throws the whole of the pits served by it out of 

 use whilst the repairs are going on. So far as possible, 

 engines are allotted to and kept for the same drivers, and 

 this is almost universally the rule in the case of passenger 

 engines on most English railways. By this plan casualties 

 are lessened owing to the greater care taken by the driver 

 in working the engine and in properly reporting defects ; 

 as a result, the coal consumption is generally less. 



Mr. F. M. Whyte, of New York, describes American 

 methods of handling locomotives at terniinals. To insure 

 uninterrupted turntable service, two turntables may be 

 supplied in a circular engine-house, the house being divided 

 into parts, each having a turntable. Mr. Whyte deals very 

 fully with the question of pooling locomotives, i.e. the 

 system of increasing the service of the locomotive by 

 placing any crew on any locomotive for service instead of 

 holding it until its assigned crew could obtain the necessary 

 rest. Extensive experiments have been made to determine 

 the relative costs of the assigning and the pooling systems, 

 and in some of these experiments no material difference 

 in cost has been found. There probably is some loss in 

 trustworthiness of service in pooling. 



Some very good drawings and photographs of American 

 engine-houses and their appliances are given by Mr. F. H. 

 Clark, of Chicago. A common length of turntable for new 

 installations i.s So feet. For boiler-washing, recent installa- 

 tions are the National, in which the steam and water 

 blown off from the engines are used for washing out and 

 for heating fresh water, and the Raymer system, which is 

 of the enclosed-heater type, and performs similar functions. 

 Mr. W. Forsyth, of Chicago, describes the arrangements of 

 the Pennsylvania Railroad at East Altoona, Pa. The 

 engine-house is in diameter and cross-section the largest 

 structure ever erected for this purpose, having an exterior 

 diameter of 395 feet and a turntable of 100 feet. There 

 are fifty-two stalls, each 90 feet deep. Mr. Forsyth states 

 that the reduction in boiler pressure from 225 lb. to 160 

 and 180 lb. has also reduced the number cf boiler failures, 

 and has permitted the more continuous use of locomotives 

 which results from the pooling system. Mr. H. H. 

 Vaughan, of Montreal, considers that in passenger service 

 poohng is objectionable under any conditions, and should 

 be avoided if possible. In freight service he considers that 

 pooling is advisable if conditions are such that engines 

 cannot be run with assigned crews. His experience is 

 that where assigned crew-s can be used on engines, the cost 

 of repairs, the amount of fuel consumed, and the class 

 of service obtained will all be more satisfactory. 



Other papers read at Birmingham were one on tooth 

 gearing by Mr. J. D. Steven, of Birmingham, and another 

 oi interchangeable involute gearing by Mr. Wilfred Lewis, 

 of Philadelphia, Pa. Mr. Steven considers the involute 

 form of tooth only, as being that which is in most 

 general use, and would welcome uniformity of opinion in 

 the matters of cutting and using gearing. If a new form 

 of tooth is desirable, it is his opinion that the stub form 



NO. 2127, VOL. 84] 



with 20 degrees angle of pressure would be a change in 

 the right direction for the following reasons : — it can be 

 used right down to twelve teeth in its true form, and cut 

 on either a single cutter or on a generating machine ; it 

 is a stronger form than that most commonly used at pre- 

 sent ; a very large proportion of its face does useful work ; 

 the possible objections on the score of less contact and 

 greater bearing pressure are so slight as to be nearly 

 negligible. 



-Mr. Wilfred Lewis is chairman of a committee of 

 standards for involute gears appointed about a year ago. 

 by the president of the American Society of Mechanical 

 Engineers. Twenty-five years ago, as a result of investi- 

 gations made on behalf of the firm of Wm. Sellers and 

 Co., he recommended the adoption of a pressure angle of 

 20 degrees in place of 15 degrees commonly used. This 

 practice has been since followed by the firm, and has given 

 satisfaction in a general way. Mr. Lewis has since 

 advocated an obliquity of ^^\ degrees as giving less inter- 

 ference on twelve-toothed pinions. Experiments on behalf 

 of the author's committee are being made at the Massa- 

 chusetts Institute of Technology, and, although not_ con- 

 clusive, enough has been done to indicate that the friction 

 loss in gear-teeth is influenced to a greater extent by the 

 length of the addendum than by the obliquity of the 

 system. 



The papers read and discussed in London dealt entirely 

 with problems connected with the electrification of rail- 

 wavs. These were contributed by Messrs. F. W. Carter, 

 of Rugby, H. M. Hobart, of London, W. B. Potter, of 

 Schenectady, L. R. Pomeroy, of New York, and G. 

 Westinghouse, of Pittsburg, the latter being the president 

 of the American Society of .Mechanical Engineers. 



Mr. Carter directs attention to electrification as a means 

 of recovering traffic drawn away from the railway by tram- 

 cars and motor-omnibuses, an expedient which has in- 

 variably been found successful in regaining much of the 

 lost traffic. Modern electric railway apparatus leaves little 

 t.i be desired in the matter of freedom from breakdown. 

 There are about 200 miles of electrified route in this 

 countrv, for the most part worked by motor coaches, 

 employing a multiple-unit system of control. There appears 

 little prospect of general electrification of the railways of 

 this country, as no advantage is apparent which woilld in 

 any way justify the expense. 



Mr. Hobart draws comparison between systems employ- 

 ing series wound, continuous-electricity train-equipments, 

 and the single-phase system. Continuous equipment pro- 

 vides, per ton of equipment, 11 horse-power at the axles 

 (averaged over the journey), as against 6 horse-power per 

 ton in the case of single-phase equipment. Mr. Hobart 

 gives figures showing that 10 per cent, less of the takings 

 are available for dividend paying in the single-phase 

 system than in the continuous-current system. 

 ' Mr. Westingliouse is convinced that the extended distri- 

 bution of electricity for industrial purposes can be secured 

 only by the generation of alternating currents of high 

 voltage and their conversion by static transformers into 

 currents of various voltages, and has developed his busi- 

 ness along these lines. He earnestly recommends to the 

 serious consideration of railway engineers and those in 

 authority the pressing need of determining the system 

 which admits of the largest extension of railway electrifi- 

 cation, and of a prompt selection of three standards of 

 electrification which will render possible a complete inter- 

 change of traffic in order to save expense in the future 

 and to avoid difficulties and delays certain to arise unless 

 some common understanding is arrived at very shortly. 



Mr. Potter considers that the development of apparatus 

 for higher voltage direct-current has so far increased its 

 scope that direct current at 600 volts or higher may be 

 considered the most economical for city and interurban 

 service. Single-phase and three-phase stock equipments 

 are applicable only to exceptional conditions. 



Mr. Pomeroy deals with the electrification of trunk lines, 

 and concludes' with the following paragraph, which called 

 forth the commendation of Mr. Aspinall, the president of 

 the Institution of Mechanical Engineers. The idea is all 

 too prevalent with the public, and even with some of the 

 bodies that have been given legal power of supervision over 

 railway companies, that any expenditure which can be 



