They were a cab-equipped variant of the previous, cabless booster (B unit) EMD DD35 (sometimes erroneously called the 'DD35B').

Like its cabless predecessor, the DD35A was essentially two EMD GP35 locomotives on a common frame, riding on a pair of 4-axle Flexicoil trucks.

The DD35s were among the last EMD road units to be built with DC generators and old-fashioned switchgear, which were more maintenance intensive than the later AC/DC equipment.

Once teething troubles had been overcome, the DD35s were reasonably successful, but they were less flexible than smaller units and thus with the economic downturn of the early 1980s they were withdrawn from service.

They spent their final months of service operating around Salt Lake City, Utah before their retirement by 1981.