The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1894-09-23
THE .THREE-wIRE TROLLEY.
This System Under Experiment for
Three Years in a Maine City.
Providence Journal.

An article in the Street Railway Reyjey
gives an interesting description Of a street
railway line operated by the t~hree-wlre
perhaps, in connection with incandescent
lighting operation. An article in one OF the
electrical Journals made reference to the
the system was only possible under double
track railroads This came under the notice
Bangor. Me. and they have accordingly
given a statement OF their experience with
the three-wire system on a single track
road for a period of about three years. The
road has a tosa, length Of ia miles of sin
gle track. Of which five and one-fourth
miles is in Bangor and two and one-half
Although both roads are run from one
power station, there is no rail functions
between them. The rail is thirty-five-pound,
one-half tram and the remainder L rail.
The rails are banded at the joints with
No. 4 copper bands and connected at each
point with supplementary copper wire. The
Houston generators, driven by four 10
horsepower turbine wheels. Each car is
equipped with two motors, and nine motor
cars are regularly operated in service. The
generators are operated in groups of two
each. and are connected IN multiple. The
positive side of one group is connected 10
earth and its negative side to the line. The
other group has. its connections reversed,
the negative side being grounded, while the
positive side is connected TO the line. The
mains run to the center of the city, whence
feeders are taken of for both the positive
and negative lines. Inere are several
branches, and on a part of the main line
there are two trolley wires of opposite po-
larity, and, of course, carefully insulated
from each other.
In order to operate the system success
fully. the road upon each side must be
equal. or nearly so. The Bangor service is
arranged for fifteen minute intervals. Every
quarter of an hour there are therefore in
the square four cars, while three are at
the end of several divisions. The smaller
line across the river is similarly balanced
by ears at both ends of the line. By ar
ranging the divisions of alternate polarity
and running cars alternately on one or the
other circuit on the section covered by two
trolley wires, the load is balanced, four and
five, which is stated to be close enough to
insure smooth running. The conditions
which led TO the adoption of the three-wire
system in this case were somewhat Pc
culiar. The power house is four and a half
miles from the nearest part of the line, and
the copper for a return circuit promised to
be very expensive. 1t was at first endeav-
ored to get q ground return by putting cop
per plates in the river at different points.
The water pumping plant for Brewer is in
the same building with the power station,
and the company found that connecting the
return wire to each hydrant gave them a
good return when this is needed. Nothing
IS said in the communication about cleo
trolysis of the pipes. 1t is stated, however,
that cars can be added to the service as re-
CURED if care is taken to preserve the cleo
trical balance. The plan would certainly
appear to be applicable TO systems operat-
ing a limited number of cars where approx
imately similar governing conditions are
met with.