A single prototype using a pair of 8 cylinder naturally aspirated 608NA prime movers (engines) was built in 1946 for the Elgin, Joliet and Eastern Railway.

The DT-6-6-2000 was most popular with the Elgin, Joliet and Eastern Railway, who purchased 27 of the 46 locomotives produced.

Several locomotives were rebuilt by the EJ&E at their Joliet shops and equipped with 1,200 hp Baldwin 606A engines.

The rest were sent to the EMD facility in La Grange, Illinois, where they were rebuilt and equipped with modified SW series hoods, 1,200 hp EMD 567C engines, and new control stands, as well as multiple-unit train control capability.

Minneapolis, Northfield and Southern Railway #21 is the final DT-6-6-2000 in existence.