The general manager of the Massachusetts Bay Commuter Railroad consortium has resigned in the face of complaints of poor service that has increased since the closing of Big Dig Tunnels last month. Paul Lundberg had been under pressure to reduce train breakdowns and other problems with the rail system, problems that have grown since thousands of extra passengers started riding the train following the Big Dig closure, according to The Boston Globe. The head of the consortium’s board of directors said Lundberg was not forced out.