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.
SUBSTATIONS—CHICAGO TRACTION SYSTEMS
| Operating Co. | No. Stations | No. Units | Total Capacity |
|---|---|---|---|
| Chicago Railways Co. | 10 | 32 | 80,000 |
| Chicago City Railway | 7 | 26 | 53,400 |
| Calumet & So. Chicago Railway | 3 | 9 | 9,000 |
| Commonwealth Edison Co. | 12 | 33 | 105,000 |
| Elevated R. R. | 3 | 8 | 9,000 |
| Totals | 35 | 108 | 256,400 |
Latest Type of 3000-Kw., 60-Cycle Synchronous Converters Installed by Commonwealth Edison Company, for Chicago Surface and Elevated Lines
The Northwestern Elevated R. R. has on order a complete 2000-kw. automatic substation from the General Electric Co. to be installed at Buena Park. This is the first application of the automatic to Metropolitan Rapid Transit service.
Distribution
Energy for elevated train operation is fed to the third-rail shoes at 600 volts. The third rail is of the top contact unprotected A.S.C.E. rail varying in size from 40 to 80 lb.