itself. Nearly 400 cars were built from 1911 to 1943. Some cars were destroyed in World War II; these cars were rebuilt from 1947 to 1949 and signed as Type TU1. To raise the economy, another 100 cars were rebuilt from 1959 to 1961 and signed as TU2. The passenger service for the T/TU-type ended in 1970, some cars were converted to working service cars and were used until the 1980s. Five cars are preserved for museum rides, four of them in service and one awaiting restoration. Type DT1 The Type DT1 was used from 1958 to 1991 in revenue service. A total of 100 cars (or 50 units) were produced. The Type DT1 had a much better acceleration than the T-type; however, their high energy consumption caused by their high weight left the Hamburger Hochbahn in dissatisfaction with the new trains, moving them into rush-hour service only in the 1970s. Most units were scrapped after their retirement while some cars were converted into working trains (retired in 2005) and three units were preserved for museum rides: The first one (516) was rebuilt between 1997 and 2000 and is used as a bar train that can be chartered for events. The second unit (512) awaits restoration until today, while the third unit (518) donates spare parts to both the other units. As the restoration of 512 has not begun by July 2018 (it is unknown whether the restoration will actually take place someday), 516 serves as the de facto DT1 museum unit. Type DT2 The Type DT2 was introduced in 1962 to replace the Type T trains. After the experiences with the heavy DT1 trains they were constructed as light-weight cars with weaker engines to save energy. A total of almost 200 units were built from 1960 to 1966. Most of them also were rebuilt in the 1980s and 1990s as their lifespan was actually only intended to be 20–25 years. The refurbished units were called DT2E, however, only the last two of five batches received a full refurbishment together with a new front design. All cars of the first three batches were retired between 1997 and 2002, with the third batch already been taken out of service in 1994 as they slightly differed from the other units (also as only two of 15 DT2.3 were rebuilt). After the official retirement in 2004, 15 units remained in service as an