260 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
Terminal yards in the heart of a city are as at present 
operated simply an abominable nuisance. ‘T‘unnels in ad- 
dition are often more or less dangerous. Any one who 
has been through the St. Louis tunnel or the St. Clair 
tunnel at Port Huron realizes that stalling a train would 
be a very serious matter, with an unpleasantly good 
chance for asphyxiation. Ventilation is at best difficult 
and seldom well done. 
The now notable experiment of the Baltimore & Ohio 
Railroad in escaping from the tunnel difficulty has proved 
  
  
  
  
  
  
  
  
  
B, T4 
so successful as to leave no doubts as to the applicability of 
electric traction to this and all similar work. 
This tunnel runs through the heart of the city of Bal- 
timore. It is 7350 ft. long, 27 ft. maximum width and 22 
ft. maximum height. Its relation to the transit through 
Baltimore is well shown in Fig. 133. The old route via the 
ferry caused continual delays and annoyance and was a 
.constant stumbling block in the way of a fast through serv- 
ice to Washington. ‘The completion of the tunnel has - 
.saved nearly twenty minutes in the time between New