The ACF 89' 4" flat car was introduced in the late 60s as a result of a continuing need for more intermodal platform capacity. The Atlas model is based on the 1973 version that was originally designed to carry two trailers or combinations with containers. The cars have been used by Trailer Train and various railroads in intermodal service since that time. Many of these were modified in the late 80s to accept longer trailers. Most of those remaining in TTX service, today, have been modified with three hitches to accommodate up to three shorter package trailers.