After World War II the trains of the Berlin U-Bahn were worn out, making a new series of trains necessary. From 1957 on the new D type trains were delivered (also called Stahldora/Steel Dora). They were made of steel, making them very heavy. In 1965, the DL type was developed, which was constructed from lighter metals (also called Dora). This way, weight was reduced by 26%. Like in earlier models, the seats were located along the sides of the train.
The first trains began revenue service on 110 326/327 (ex 2030/2031) and 110 306/307 (ex 2008/2009) in March 1988 via Alexanderplatz connecting tunnels. They were called DI in the east. Of course, they were painted in the East Berlin color scheme of ebony and yellow.
7 trains (110 386-110 397, also known as 2096 to 2099 and 2102 to 2109) all returned to BVG early in November 1990. After the merger of BVB with BVG in January 1992, these trains continued to deploy on the U5, U6, U7, and U8 until their retirement in 1998-99. The last trains of the 'D' type were retired in 1999, and they were sold to Pyongyang Metro in Pyongyang, North Korea
