NA TURE 



461 



THURSDAY, APRIL 11, 1878 



THE APPLICATION OF ELECTRICITY TO 

 RAILWAY WORKING 



The Application of Electricity to Railway Working. 

 By William Edward Langdon, Member of the Society 

 of Telegraph Engineers ; Superintendent (Engineering 

 Department) Post-Office Telegraphs ; and late Super- 

 intendent of Telegraphs on the London and South- 

 Western Railway. (London : Macmillan and Co., 

 1877.) 



IF any proof were needed of the vast and important 

 services that science has conferred upon man, no 

 more eloquent example could be instanced than that 

 great combination of the conceptions of Stephenson and 

 of Volta — the locomotive and the voltaic battery — which 

 combination in its elaborated form is known as the rail- 

 way system of the present time. 



Living as we do in the midst of conveniences of transit, 

 the mere belief in the possibility of which would, fifty 

 years ago, have made a man a fit inmate for a lunatic 

 asylum, we are apt to lose sight of the complexity of the 

 problem that has been solved and to forget the all-im- 

 portant part which science has played in rendering such 

 a state of things not only possible, but an accomplished 

 fact of so familiar a nature as to have become a necessary 

 part of our very existence. But when it is remembered 

 that upon most of the lines of railway in and around 

 London several hundred trains are running^daily ' at inter- 

 vals varying from three minutes to half an hour, that each 

 of those trains requires a separate series of signals only 

 to protect it from collision, and that interspersed with the 

 regular traffic "specials," "light engines," and trains out 

 of time have to be provided for and protected against (to 

 say nothing of the goods traffic, or. of shunting, crossing 

 and junction operations), it will be readily understood 

 that traffic management, holding in its hands the power 

 of life and death, is no easy task ; and that without some 

 very elaborate combination of sound administrative 

 organisation with scientific instrumental aid, the traffic 

 of a single hour would soon become an inextricable 

 tangle of confusion. 



Notwithstanding the great importance of the subject, 

 involving as it does the safety of millions of human lives, 

 it is somewhat surprising that technical literature should 

 hitherto have been devoid of a work upon the very 

 essence of safety in railway working — the application of 

 the electric telegraph and of electric signalling to traffic 

 management. This need has now been very ably sup- 

 plied by the work before us, every page of which bears 

 upon its face the evidence of being written by a thoroughly 

 practical master of the subject in all its details and rami- 

 fications, and at the same time by one who possesses an 

 exceptional power of making the subject clear to his 

 readers. 



In a handbook of a particular application of electricity 

 it is refreshing to find that no valuable space is occupied 

 by matter to be found in every elementary text-book of 

 physics, that neither Thales with his amber nor Galvani 



' During some portions of the day as many as sevenly-five trains run 

 through Clapham Junction Station in an hour, and between 900 and i,o«o 

 is the daily aggregate average. 



Vol, XVII. — No, 441 



with his frogs are even mentioned, and that descriptions 

 of the various forms of the voltaic battery find no place 

 in the book. The author presupposes that the necessary 

 elementary knowledge is possessed or can be obtained 

 by his readers, and disposing in one page of a few neces- 

 sary introductory definitions plunges at once into his 

 subject. 



The work is arranged in three principal divisions : — 

 (i) Speaking telegraphs; (2) Block signalling; and (3) 

 Miscellaneous appliances. Under the first division a 

 chapter is devoted to descriptions of the various speaking 

 instruments and of the methods by which they are worked. 

 The second chapter treats of signalling regulations, and 

 while being of special value to all professionally engaged 

 in railway working must prove most instructive and inter- 

 esting to outsiders, who are thereby let into some of the 

 technical mysteries of telegraphy. Every one is familiar 

 with blank spaces left at the head of the telegraph forms 

 issued by the Post Office, against which are printed the 

 words " Prefix," " Code time," " Words," &c., but compa- 

 ratively fe w know their meaning. The Prefix to a telegram 

 is a signal letter or abbreviation to indicate the character 

 of the message which follows, and therefore the order of 

 its precedence for transmission. The Code time is a 

 similar abbreviation to indicate the exact time at which a 

 communication is handed to the telegraph clerk for trans- 

 mission ; and the space marked " Words " is set apart for 

 signalling to the distant station the number of words con- 

 tained in a message which gives to the receiving clerk a 

 check upon his correct reading of the signals by which 

 the communication is transmitted. 



In railway telegraphy the prefix D.R. (Danger) gives 

 to the message precedence over all others, and should 

 never be employed except in cases of great emergency. 

 Other prefixes SP. (for special service), DB. (for 

 ordinary traffic), and various others are employed in 

 railway signalling, by which the degree of its urgency is 

 indicated before the message itself is transmitted. 



The system upon which the Code time is abbreviated is 

 very ingenious, and will be readily understood by referring 

 to Fig. I, which we have borrowed from Mr. Langdon's 

 book. Opposite the hour figures on the dial of a clock are 

 placed the twelve letters, A, B, C, D, E, F, G, H, I, K, L, 

 and M, and against the four minute divisions between the 

 hour figures, are placed the letters R, S, W, X, which, as 

 will be seen in the sketch, are repeated all round the dial 

 A simple time-code is thus obtained, by which any hour or 

 minute throughout the day can be expressed in from one 

 to three letters ; thus 2 o'clock would be signalled by B, 

 2.45 by BI, and 7.12 (the time shown in the figure) by 

 G, B, S, that is, G for seven hours, B for ten minutes, and 

 S for the remaining two minutes to make up the twelve. 



The technical regulations for railway telegraphing and 

 traffic management are treated very fully. In this the 

 author's large experience from having had the superin- 

 tendence of the telegraphs of one of the most important 

 lines of railway in the country is most apparent and gives 

 great weight to his remarks, which ought to be committed 

 to memory by all concerned in the management of rail- 

 ways ; for if rigidly enforced and carried out, railway 

 accidents would become well-nigh impossible, except from 

 failure of instruments, from the breaking-down of rolling- 

 stock, or from damage to permanent way. 



