A highway overpass in southeast Missouri collapsed early Saturday when rail cars slammed into one of the bridge’s pillars after a cargo train collision, authorities said. Seven people were injured, though none seriously. The bridge collapsed after a Union Pacific train hit the side of a Burlington Northern Santa Fe train at a rail intersection. Derailed rail cars then hit columns supporting the Highway M overpass, causing it to buckle and partially collapse. The National Transportation Safety Board launched an investigation into the cause of the cargo train collision, which happened about 2:30 a.m. near Chaffee, a town of about 3,000 southwest of Cape Girardeau. Only two vehicles were on the overpass at the time. Five [...]