At the very least, the Chicago, Aurora & Elgin was almost universally third rail. The only exclusion was the yard in Wheaton, IL, where overhead was used out of concern for worker safety. The L is still third rail, as well.
The CA&E ran a minimum of two-car sets, to deal with level crossings. Crossings could only be made so wide as to allow a two-car set to bridge the gap. I know their freight motors weren't particularly long, so as to allow occasional turns around the Loop, so I don't know what they did for crossings there.