674 PKOCEEDINGS OF SECTION H. 



direction on the main and branch lines simultaneously, but where 

 the actual junction is pasU the " down " end of the platform the 

 circumstances are entirely different. In this case the branch and 

 main lines past the " down " end of the platfoi'ms form one connected 

 and continuous section, and to permit trains to approach from the 

 branch and main lines simultaneously under any circumstances with 

 a junction thus arranged is clearly a breach of the fundamental 

 principle of block working. The attached diagram, No. 2, illustrative 

 of the arrangement of the Hawthorn Junction Station, Victoi-ia, may 

 be taken as an excellent example of a well laid out junction between 

 a double and a single line at a station, the single line being accom- 

 modated at an island platform, and coming in from the right when 

 facing towards the metropolis. It will be understood that all points 

 and signals are interlocked, and that plunger bars are provided with 

 all facing points. The general arrangement is as follows: — When 

 trains are passing, either up or down on the main lines, the catch 

 points on the branch are set to divert any branch train to the 

 siding, and when a train for the branch (i.e., a down branch train) 

 comes along it is diverted by the second facing points to the platform 

 road of the branch line, and cannot foul anything when a train is 

 passing from the branch to the "up" main line {i.e., an "up "branch) 

 the first facing points of the down road are set to divert any approach- 

 ing down train into the No. 2 branch road. Hence the only possible 

 collision would be caused by an '' up " main line train passing 

 through whilst an " up " branch line train was passing on the main 

 line, and to do this the " up " main line train would have to pass 

 distant home and starting signals all at danger. 



Diagram No. 3 illustrates the corresponding arrangement where 

 the branch comes in from the opposite side, and it will be noted that 

 the protection cannot be made as complete, since an " up " main line 

 train can foul a " down " branch line train as well as an " up " one. 

 The former could, of course, be avoided by adopting a " flying 

 junction." 



