130 



Professor H. S. HeU-Shaii. 



[March 31^ 



graphical form the quickening in speed from the opening of the line 

 in 1880 to the present time. You will notice that this increase of 

 speed has been followed by remarkable results ; the first immediate 

 result is the possibility of a greater number of trains, and the curve 

 of the rise in the number of trains is shown on the diagram ; but the 

 really significant feature is the rise in the number of passengers 

 carried, 35,000,000-72,000,000, which is the direct result of the 



METROPOLITAN - DISTRICT RAILWAY 

 (mansion mouse to EALINS ) 



increased facility in travelling. Now it is in such a case that the 

 importance of the signalling and braking come to be almost pre- 

 eminent, quite apart from the mere mechanical problem. 



I may point out that the District Railway, in common with most 

 other electric railways of this country, has what is known as a " track 

 system of signalling," which, apart from the fact that the driver holds 

 what is known as "the dead man's handle," which upon being 



