86 Book of Engineering 



side of the stream, just before the rapids 

 are reached, a cutting into the bank is 

 observed to which the tug is headed. So 

 soon as the tug and its burden are within 

 the channel it is observed that it takes a 

 curve to bring it parallel with the river, 

 though it left it at right angles. 



Along the centre of this channel piles 

 have been sunk, and care has been taken 

 to ensure that whatever the state of the 

 stream, there shall always be sufficient water 

 to cover the piles. As the channel goes on 

 the piles come nearer and nearer the sur- 

 face. Upon the piles, towards the end of 

 the channel, a mono-rail is laid and the 

 wheels which are placed within the saddle 

 of the double hull engage upon the rail so 

 soon as the river train is drawn sufficiently 

 on to the slight upward slope of the 

 piles. 



The piles go on to dry land and the 

 mono-rail is laid across them until a similar 

 channel is encountered beyond the rapids, 

 where the river train takes to the water 

 again by reversing the process just described. 



