The embattled boss of German railways has quit.Deutsche Bahn’s Chief Executive Hartmut Mehdorn has stepped down following revelations the company used private detectives to spy on staff as part of what it said were anti-corruption measures and secretly monitoring and even deleted their emails. Mehdorn said he did not know anything about that and had done nothing wrong but was leaving to “to put an end to the destructive debate.” He had been praised for turning Deutsche Bahn into a profitable global transport leader during the 10 years he ran it but also strongly criticised for a confrontational approach to unions. His fate was sealed when it appeared he had lost the support of German Chancellor Angela Merkel. She said: “He has brought the company back on track financially and transformed it into a logistics firm that is respected around the world.” Merkel’s reluctance to continue to defend Mehdorn may be connected with the fact that she faces a federal election in six months. One report said Thomas Enders, chief executive of Airbus, is being considered as a successor. Mehdorn was supposed to retire in 2007, but stayed on to oversee the part privatisation of Deutche Bahn. That has been postponed due to the economic crisis and ministers said it is unlikely to happen for several years.