the stadtbahnwagen typ b (translation "type "b" light rail vehicle", short form b-wagen) is a light rail vehicle used by several stadtbahn networks in the german state of north rhine-westphalia. it was mainly developed by düsseldorf-based duewag, who also built the majority of vehicles in a consortium with siemens and kiepe. a small series of ten units was built by waggon union in berlin. as the type evolved over two decades of production, some vehicles have little more in common than their outer dimensions and the basic configuration of a two-part multiple unit on three bogies with both outer ones powered. for the dortmund stadbahn, some cars were modified with a central section and a fourth bogie. these vehicles are referred to as "b8" or " b80c/8" (eight axles). these vehicles have a length of 38 m (124 ft 8.036 in) and a weight of 49 t.