Dortmund is a German-speaking conurbation and a part of the Traktionstadtsgesellschaft. There is also a real city of the same name. During the final battle of the Green Storm War, Dortmund and Darmstadt were bogged down in the Rustwater Marshes and it's likely they were destroyed when ODIN was turned on the Traktionstadtsgesellschaft, as Harrowbarrow received a distress signal from the city that quickly went dead.
According to the Traction Codex, Dortmund was the only Conurbation in the Traktionstadtsgesellschaft by the time of the War, with all towns linked together by bridges and walkways - this would make it a Quasi-Conurbation. The Conurbation began to form around 1005 TE, and had become a Quasi-Conurbation at 1012 TE .