262 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
the axle, but with a clearance of about 13/ ins. On this 
armature shaft is carried a five-armed driving spider which 
bears on lugs on the driving wheels through intermediary 
rubber cushions. The axle is thus relieved of the direct 
weight of the armature and there is sufficient flexibility to 
take up vibration due to irregularities of track. ‘I‘he loco- 
motive is fitted with air brakes and air whistle, and a 
headlight at each end. 
The supply of the immense current demanded by such 
a locomotive at full load was a difficult matter and the 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
need was met by a most ingenious and effective, though 
from our present point of view too complicated and costly, 
arrangement. ‘This was a species of reversion to the slotted 
tube used on some of the earliest foreign electric roads, 
from which current was taken by an interior brush some- 
thing like a gun cleaner. In this case, however, the tube 
was built up of two angle irons bolted to a covering strip 
and weighing about ninety pounds per yard. The channels 
thus formed are carried on trusses in the open and sus- 
pended from the arch within the tunnel. Fig. 136 shows 
the character of the hollow working conductor and the 
      
   
   
   
  
  
    
   
  
  
   
   
   
   
  
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T I R TI