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
e
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