RAILWAY CONSTRUCTION. 303 



valve can be opened or closed by the small hand-wheel B, which 

 is conveniently accessible to the man on the tender. On the 

 above sketch (Fig. 463) the water column is shown placed at an 

 ordinary normal distance from the rails ; but in cases where 

 there is considerable .space between the two lines of rails, or 

 where a platform intervenes, the swinging arm may be extended 

 out to the necessary length, and counterbalanced as shown in 

 Fig. 464. 



