I found this photo at My Link page Dave's Electric Railroads, located to the right of Your computer screen at www.davesrailpix.com

This photo comes to us from the Bill Volkmer collection.

By the late teens and early 1920's era, Chicago's early small 4 wheeled electric streetcars from the late 1800's, were at the end of their service life.

This 1890's era example from the Chicago City Railway Company, has been replaced by newer and larger double truck city streetcars. This little 4 wheel streetcar, is now working it's final years in company maintenance service as a work motor.

This practice is still done today with transit buses in Chicago and other citties.
Older transit vehicles with a few good operating miles on them yet, many times are demoted to the company maintenance department.

Thanks.
Eddie K.