RAILWAY CONSTRUCTION. 347 



ballast or construction trains, as a staff may be taken out of the 

 instrument F at station E, which will give possession of the 

 section as far as station H, and when the ballasting operations 

 which may be very near to E are completed, the train can 

 return to E, and deliver the staff again to the instrument F, 

 instead of having to run the entire distance to station H. 

 Although carrying a train-staff', the engine-driver must approach 

 stations cautiously, and obey the fixed signals in the usual 

 manner. 



