The Hamburg Hochbahn is an elevated railway system on standard gauge track with 750 V power supply. The first cars came into service in 1912 and there were 13 original series delivered (1. - 13. Lieferung)
By the 1950s, the vehicle fleet was elderly, most still using the original trucks and equipment.
The first of the 50 new DT1 series double car sets arrived during May 1958 in Hamburg and the last was in service by July 1959. They were built by the Waggonfabrik Uerdingen, with electrical equipment by SSW, AEG and Knorr, achieving a maximum speed of 80 km/hr.
The 100 individual cars were numbered 9431-9530 between 1958-1960. They ran in coupled sets of 2 cars with close coupling. In 1960 they were renumbered to 9000-9099.