92 POWER DISTRIBUTION FOR ELECTRIC RAILROADS.
adopted by various roads. Balancing is accomplished by
various means. ‘T‘he simplest is shown in Fig. 55. Here
we have a single track road with two lines, A B and C D.
T'he tracks are connected to the neutral lead while the +-
and — feeders run to the separate branches as shown.
T'his balancing is not very close since it is no easy matter
1
S
1
500
<—1000
Track
FIG. 54
so to divide a branched road that the loads on the two
parts shall be equal. Another arrangement less simple,
but giving more uniform balance, is shown in Fig. 56.
Here the whole track is divided into sections alternately -
and—. On double roads either one track is supplied from
the -+ feeder and the other from the —, or each track is
subdivided as in Fig. 56, the latter being the preferable
method as it preserves the loads on the two sides more
uniformly.
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F1G. 55. e
A zonal system might be used in large systems, all
track within one zone being supplied from the - side, all
in the next zone from the —side and so on. In general
however the plan of Fig. 56 carried out onall the lines as
systematically as the location of the track allows is the best
method. ‘The sections may properly vary from a few hun-
dred to several thousand feet in length according to the
nature of the car service and local conditions. Very many
sections should be avoided as the break piecesin the trolley
wire are somewhat annoying.