Budd manufactured 119 cars for the Burlington Northern Santa Fe line between 1950 and 1973, all with the same basic design.
Most of the cab control cars were acquired by the West Suburban Mass Transit District (WSMTD) in 1973, finally enabling all Burlington Northern trains to be push-pull. Only six cab control cars existed prior to then, and were usually only used on trains requiring a quick turnaround.
Cars 7100-7121 acquired by the WSMTD were built with narrower fluting than the earlier cars, and look more like the Budd cars acquired for the Milwaukee Road and other lines.