I found this historic early 1970's era photograph from the Chicago Transit Authority at My Link page "Tom's Trolleybus Pictures", located to the right of Your computer screen at
http://www.trolleybuses.net/
I was born in Chicago Illinois in the year of 1962, and I have happy childhood memories of riding and observing the CTA electric trolleybuses, during their final years of operation on Chicago's city streets.
The era of the electric trolleybus in Chicago, began in 1930 with the opening of the Chicago Surface Lines Comapny Rt # 76 Diversey Avenue line on April 17th, 1930. Soon other routes like the CSL RT # 85 Central Avenue line would soon follow.
After the electric streetcar was introduced and began operations in Chicago in 1893, it would not be long before the city of Chicago Illinois would have the worlds largest streetcar system by the early 1900's.
By the 1930's, new electric streetcar lines were expensive to build and maintain in America's Great Depression era ecoonomy. The Chicago Surface Lines introduced electric trolleybus routes on the north side of the city in 1930, and they would originally serve as feeder routes offering service extension for a few miles at the end of the streetcar terminals.
After the Chicago Transit Authority began operations on October 1st, 1947, the agency wanted to phase out electric streetcars and replace them with cost effective transit buses. Most of the trolleybus routes in Chicago, were actually former streetcar routes that were primarilly located on the north side of Chicago.
With the overhead wires already in place and online infrastructure facilities like electrical substations still in daily use, it was cost effective at the time to add a second overhead wire on each side of the street, and equip these former streetcar routes with electric trolleybuses. The electric trolleybuses also operated on 600 volts DC like the electric streetcars, but required an extra overhead wire to complete the circuit, as electric streetcars completed their circuit through the tracks in the street. Trollybuses required a hot and ground connection via two trolly poles and twin overhead wires.
Chicago's electric trolleybuses proved to be a maintenance headache, and were very less than cost effective in the long run. By the late 1950's, the CTA began a slow phasing out of the electric trolleybus routes, and replace them with new diesel and propane powered buses.
Chicago's troleybus era ended on Sunday, March 25th, 1973. These 1951 CTA Marmon Harrington trolleybuses, are viewed parked at the North Avenue garage at West North and North Cicero Avenues in February of 1973, one month before the official end of Chicago trolleybus operations.
The CTA North Avenue garage was eventually demolished and replaced by a large outdoor retail strip mall today.
