A train derailed this morning in Bangor. Anthony Riitano, assistant chief with the Bangor Fire Department, said two tank cars carrying Carbon Dioxide tipped on their sides. There is concern that with the heat the tanks could vent, but Riitano said there is no concern for public safety. The derailment happened in the area of Riverview Street at the Bangor-Veazie town line. The Department of Environmental Protection has been notified.