FAST AND HEAVY RAILWAY SERVICE. 239 
The character of the overhead structure in this part of 
the line is well shown in Fig. 124. The greater neatness 
and simplicity of the third rail arrangement is obvious. 
Until this experiment fear of serious leakage has deterred 
engineers from using such construction on ordinary road- 
beds. A regular railroad construction with rails carried 
  
  
  
  
  
  
YIG. 124. 
on ties slightly above the surface of the ground is very 
much less liable to leakage than street railway construc- 
tion with nearly buried rails, particularly since in the 
former the third rail can be supported on adequate insu- 
lators. 
Sesides this, an amount of leakage which would be 
formidable in street railway work may be relatively quite 
small in the heavy service of a suburban line. The third