General Motors used lightweight construction concepts in the building of a futuristic locomotive and 10 cars, which resulted in the "Aerotrain." It was an attempt to lure passengers back to rail travel vs. air or automobile travel. Unfortunately, at high speeds the coaches rode very poorly and were very noisy since they were little more than widened bus bodies. The Chicago, Rock Island and Pacific ultimately used the trains as commuters from Chicago to Joliet, IL. Hear more here.