carriers attached to the sections of railway line, thereby
forming a portable section of the electric railway, as illustrated by
Fig. 2. The steel carrier or "arch" is fixed to one of the sleepers,
which is made of sufficient length for that purpose. On the straight
line these line supports are placed about 25 yards apart. In curves of
a small radius each section of tramway is provided with an arch, to
keep the line of the wire as nearly as possible parallel to the curve
of the line. Apart from these special extended sleepers with wire
carriers attached, the line is constructed in the ordinary mariner
with rails 14 lb. per yard and upward. As the electric locomotives are
lighter than steam locomotives, the weight of rail required is
somewhat less. The special trolley for erecting the wires along the
railway line is shown in Fig. 3. This consists of an ordinary four
wheeled platform wagon with ladder, and wire drum with tightening gear
and clamps or grips for anchoring the trolley to the line. The wire is
led over a sheave on top of the ladder and fixed to the picket post at
the beginning of the line. When erecting the wire the trolley is
pushed beyond the first carrier arch, clamped on to the rails, and the
wire is then tightened by means of the tightening gear. It is then
firmly fixed to the insulator on the carrier arch The tension in the
copper wire is taken up by a second portable ladder, which is also
provided with a tightening gear and can be clamped to the rails in the
same manner as the trolley, so that the trolley can then be pushed
behind the second carrier arch and the process previously described
repeated. By the tension in the wire the carrier arches acquire the
necessary stability, while without the procedure previously described
it would be impossible to use such light arches attached to the
sleepers. On permanent lines, the extreme ends of the wire are
attached to properly anchored picket posts. On portable lines, on the
other hand, the trolley with the wire drum is fixed to the rails at
the end of the line, as shown in Fig. 3, so as to enable the line to
be lengthened or shortened, as may be required, with ease.

[Illustration: FIG. 3.--THE STRAINING GEAR AND TERMINAL ANCHOR.]

Care is taken in insulating the drum and ladders so as to prevent
leakage from this erecting trolley to earth. The feeders from the
power house to the overhead wire and to the rails respectively are
erected on light iron posts,