══════════════════════╤═══════╤═══════╤═══════╤═══════
│ Route │Single │ Yard │ Total
│ Miles │ Track │ │ Track
│ │ Miles │ │
├───────┼───────┼───────┼───────
Northwestern Elevated │ 19.7│ 52.33│ 9.28│ 61.61
Chicago & Oak Park │ 9.32│ 20.38│ 2.28│ 22.66
Metropolitan West Side│ 23.83│ 53.63│ 7.78│ 61.41
South Side │ 16.15│ 35.99│ 9.97│ 45.96
Loop │ 2.12│ 4.72│ ....│ 4.72
├───────┼───────┼───────┼───────
│ 91.12│ 167.05│ 29.31│ 196.36
──────────────────────┴───────┴───────┴───────┴───────
[Illustration: CHICAGO ELEVATED RAILROADS]
[Illustration: TRAIN ON INTRAMURAL RAILWAY CHICAGO, 1893]
[Illustration: 8-CAR TRAIN—CHICAGO ELEVATED ROADS—EQUIPPED WITH GE-243
MOTORS]
[Illustration: 4000-KW. SYNCHRONOUS CONVERTERS AT CAMPBELL AVENUE AND
HOMER STREET STATION]
_Power Supply_
The power for the early elevated lines was derived from engine-driven
direct-current power plants all of which have since become obsolete. All
power, therefore, is supplied from the network of the Commonwealth
Edison Co., which maintains an ample reserve to supply all needs. While
a large percentage of the power now being purchased is generated at 25
cycles, the policy of the Power Co. on all new equipment is to specify
60 cycles.
_Substations_
12 out of the 32 substations supplying the various traction systems are
owned and operated by the Commonwealth Edison Co. and only 60-cycle
generating equipment is installed when adding to their present capacity.
The several substations contain synchronous converter units ranging in
size from 1000 to 4000 kw. each. The preferred size for new 60-cycle
substations is the 3000-kw. unit of which there are now five in service.
The following table shows the ownership and gross capacity of the
substation equipment for all of the Chicago lines. It is not possible on
account of the diversity of feeding arrangement to designate any
particular stations as belonging exclusively to the elevated lines.