In 1937 NSB ordered two test unit for a diesel-electric locomotive from Krupp in Germany with the engines being delivered from MAN. Due to the start of World War II, the delivery was delayed, and in 1942 the only delivered locomotive arrived in Norway and given the number 1 601. Probably due to the conditions in the German industry at the time, where most of the resources went to the military industry, the locomotive was plagued with faults and was never especially successful. In the 1950s NSB chose to instead order the Di 2 and Di 3 units for the diesel operations. The Di 1 unit was taken out of service and destroyed in 1959.