SAFE RAILWAY WORKING. 673 



substantial guarantee that the way is clear before him to the end of 

 the section, or at least that no train is, approaching him from the 

 opposite end, and the only satisfactory way of gi\^ng such an assur- 

 ance is to put him in possession of the only sectional staff, ticket, or 

 tablet which can at the time be away from the stations. 



In South Austi-alia, on lines with light traffic, the " pei-missive 

 block " system is used, but the regulations provide that a consider- 

 able time, usually 40 minutes, must elapse before the departure of a 

 following train. 



In connection with the double line working in Australia on most 

 of the lines a satisfactory system of interlocking between points and 

 signals exists, and also a more or less satisfactory system of block 

 working, as already indicated, but in the majority of cases thei-e is 

 no guarantee (except i-eliance on the -signalman) that the signals 

 agree with the^ block instruments. To put it another way, except 

 where the " lock and block" system is in use, there is nothing to 

 prevent a signalman letting a train into the section before he has 

 ■'line clear." Where trafihc is veiy heavy the "lock and block" 

 system has been introduced at very considerable expense, and, as is 

 well known, with that system the train itself sets the signals at 

 danger behind it, and keeps them there until it clears the section. 

 In many cases the expenditure necessary for the equipment would 

 not be justified, and in such cases the writer suggests that electrical 

 connections should be made between the block instruments and the 

 stai'ting levers, so that the latter cannot be pulled off unless " line 

 clear'' has been obtained from the station in advance. Such an 

 arrangement Avould cost but little, and would be a giiarantee of 

 increased safety. Further, at junction stations the block instniments 

 could be readily interlocked electrically, so that " line clear" could 

 not be given at the same time to two or more trains which could foul 

 each othei'. 



(b) Akrangemen't of Juxctiox Stations. — Whilst no rule can be 

 laid down suitable for universal application, it will generally be- 

 found practicable (and where practicable, certainly desirable) to so 

 arrange junction stations that the passenger platforms and "the 

 entrances to the goods yards (if any) are located past the point at 

 which the main and branch lines separate, as under such circum- 

 stances a train stopping at its platform or shunting will block its 

 own line only. To put this in different language, it is usually desir- 

 able that the actual junction be in the " up " direction from the 

 passenger platfoi-ms. With this arrangement, and accepting the 

 starting signals as the boundaries of the sections, it will be noted 

 that the main line and branch line sections on the " down " side of 

 the junctions are entirely separate. It may be accepted that any 

 section is effectively protected when there is at its entrance a starting 

 signal, with a home signal a quarter of a mile further back, and a 

 distant signal at the usual distance in the rear, since it is most 

 unlikely, though, of course, possil^le, more especially in fogs, that a 

 driver will, by any mischance, run past two absolute stop signals 

 when he has been previously warned by a distant signal that they 

 are at danger. Hence, with a junction so arranged, it is reasonable 

 to permit trains to approach the junction station in the "up"' 



2s 



