FAST AND HEAVY RAILWAY SERVICE. 263
method of supporting it in the tunnel. Current is taken
off by a snug-fitting brass shuttle carried on a toggle joint
trolley frame, and leading to the motors by a flexible cable.
Fig. 136 givesa clear idea of this trolley structure, which in
practice does its work exceedingly well. Save for occa-
sional trouble before the conductors were cleared of rust
and dirt, at the very first, the arrangement has left little
to be desired. The conductor in the tunnel is supported
every fifteen feet, and outside the tunnel the spans are thirty
to sixty feet. ’The trolley support has great lateral flexi-
bility and the working conductor is normally alongside the
locomotive rather than over it.
S8ECTION THROUGH MAIN TUNNEL.
FIG. 137.
The power house is near the southern terminus of the
electric system and current is taken from it to various
points on the line over 1,000,000 ¢. m. feeder cables. The
working conductor is carefully bonded at each joint by two
No. oooo bond wires.
Now as to operation. After continuous service for
more than a year, the system has shown itself to be
thoroughly efficient and reliable. Repairs have been light,
the working conductors have been easily kept clean by
running through a scraping shoe every two or three weeks,
the leakage current in spite of the moisture of parts of the
tunnel and very dirty insulators has been only about
four amperes.