CHAPTER V. 



Sorting-sidings Turn-tables Traversers Water-Tanks and Water-Columns. 



Sorting-sidings. On many important long main lines it is 

 necessary to establish special independent sidings for sorting or 

 arranging waggons of merchandise and minerals. Where there 

 are only two lines of rails to serve for the UP and DOWN 

 service of a heavy passenger and goods traffic, it is imperative to 

 restrict those lines as much as possible to the actual transit of 

 trains, and not to block them by unnecessary occupation for 

 shunting purposes. A goods train running a long distance 

 collects waggons from many roadside stations, and at some of 

 them several waggons will be taken on, to be forwarded to 

 various and widely distant destinations. The accumulated train 

 comprises waggons which must be divided out into groups, to be 

 passed on either to distant sections of the same railway system, 

 or on to neighbouring lines. To avoid interruption to the train- 

 working, and the delay of complicated shunting operations at the 

 roadside stations, the waggons are attached just as they are 

 dicked up, and the work of sorting is allowed to stand over 

 until the train arrives at the place assigned for the purpose. A 

 site for sorting-sidings is generally selected where the ground 

 and gradient are favourable, and where ample room can be 

 obtained for a large number of short parallel lines, with space for 

 future extensions. The arrangement that naturally suggests 

 itself is that of a series of fan-shaped sidings leading out of main 

 shunting lines, separate from the main-traffic lines. In some 

 cases the sorting-sidings are laid down with dead-ends, as in Fig. 



434, and in others they are made as through sidings, connecting 

 at both ends with shunting lines and main-traffic lines, as in Fig. 



435. Each of the sidings is usually made sufficiently long to 

 hold a complete train of sorted waggons, and the number of 



