These units were powered by a naturally aspirated eight-cylinder diesel engine rated at 1,000 horsepower (746 kW), and rode on a pair of two-axle trucks in a B-B wheel arrangement.

The work was performed at EJ&E's Joliet, Illinois workshops, and produced a finished unit that featured an offset exhaust stack and left-side turbocharger bulge, the latter being much like that found on Baldwin road switchers.

The units were stripped to their bare frames (the original trucks and distinctive cast steps were left in place) and fitted with 15-foot (4.6 m)-long steel cabins.

In December 1970 the Atchison, Topeka and Santa Fe Railway (soon after its successful CF7 capital rebuilding program) produced a unique switcher locomotive, known to railfans as the "Beep", at its Cleburne, Texas service facility.

The company hoped to determine whether or not remanufacturing its aging, non-EMD end cab switchers by fitting them with new EMD prime movers was economically prudent.