I found this photo at My link page Tom's Trolley Bus Pictures to the right of Your computer screen. www.trolleybuses.net

This is a rare late 1960's era behind the scenes view of Chicago Transit Authority maintenance and support operations.

A practice that transit companies have done going back to the electric stretcar era, was the demotion and reassignment of older equipment to the company maintenance department. This photo wich was taken at the CTA Forest Glen Garage on North Elston Avenue and is dated for May 18th, 1969, shows a now demoted and repainted CTA 1950's era General Motors transit bus, serving in work bus service.

The CTA electric powered trolley bus lines, were operating in their final years of service. This diesel powered transit bus, has been equipped with special roof mounted trolley poles fitted with sleet scraper blades. These were used to scrape ice off the overhead trolley wires during the winter season.

The Chicago Transit Authority phased out the remaining electric powered trolley bus routes, on Sunday, March 25th, 1973. The last two CTA electric trolley buses that actually operated on the last day, are preserved and occasionally operated today at The Illinois Railway Museum in Union Illinois. www.irm.org

The GM bus that is seen here, proboubly operated in maintenance work bus service for perhaps another ten years or so for the Chicago Transit Authority before retirement.