The Hamburg Hochbahn is an elevated railway system on standard gauge track with 750 V power supply.
During the Second World War, Hamburg lost 125 U-Bahn cars (29% of their fleet) through bombing raids. Trucks and other parts were retrieved from 118 cars.
The A-wagen cars were rebuilt into the B-wagen cars after the Second World War. The prototype rebuilt car was completed in 15th November 1947 by the Falkenried works.
The main series of cars was rebuilt from 1948 - 1953 by Falkenried, Talbot (Aachen), Fuchs (Heidelberg), AEG and Siemens. They later became known as TU1 cars from 1958.
The cars were removed from service between early 1965 and May 1970. Car 8838 (ex 324) was reserved for museum preservation.