This weekend is a great train show at the trainyard Heddernheim of the U-Bahn Frankfurt to celebrate the 50th anniversary of the U-Bahn.

U-Bahn Car of the U3 series. Those cars were concepted for a use when the U-Bahn was converted to a full metro. They even were concepted for a third rail use. In the end they were less used than planned. They were in service from 1980 to 2017.