The New York, New Haven and Hartford Railroad received special permission from the War Production Board to purchase #0710–#0759 as dual-use (passenger/freight) locomotives; they were built between 1942 and 1945.

The first ten, numbers 0700 through 0709, were delivered starting right after the attack on Pearl Harbor in December 1941 from ALCO's Schenectady factory, allowing the road to prove their freight-hauling abilities just in time.

The 9-30-1945 Summary of Equipment designates four different classes: DER-1 (Diesel-Electric Road) units #0700–#0709 had the original design with a mass of vents on the roof, DER-1b (#0710–#0719) were nearly identical, with square winterization hatches over the roof fan housings (which were also applied to the original units following the winter of 1941), DER-1b (#0720–#0729) and DER-1c (#0730–#0759) all had simplified rooflines, and other minor variations in appearance.

In the Winter of 1953 to 1954 New Haven A-A-A units #0720-0722 with #0721 in the lead could be seen in far northern Maine on the Bangor and Aroostook Railroad, helping haul massive tonnage of potatoes, usually in the now-famous red white and blue "State of Maine" products reefers.

Eventually #PP716 became the last DL-109 on the face of the earth and fell to the scrappers torch under the Penn Central at Dover Street Yard in Boston, in August 1970.

The Rock Island had rival builder EMD repower their newest, the #621, with dual V12 567B engines but this does not seem to have extended its career greatly.

The electric motors and prime movers were sent to ALCO for rebuilding, and the shopmen at the Milwaukee Road's Menomonee Valley shops rebuilt the locomotives.

The units then worked on secondary lines to Canton, South Dakota, Green Bay, Wisconsin, and Madison-Chicago trains until retirement; #14B was finally scrapped at Jones Island in Milwaukee in May 1964.