On a gloomy November morning the night train to Strasbourg (EuroNight 468) passes through the forest at Forchheim, just south of Karlsruhe. It is lead by Deutsche Bahn's 181 213, an express passenger electric, designed in the 1970's to run under both Germany's 15 kV, 16?2?3 Hz AC and France's 25 kV, 50 Hz current.