The rural Missouri railroad crossing where an Amtrak train struck a dump truck before becoming derailed, an incident that killed three and injured dozens on Monday, is among several where potential safety hazards had already been identified in a recent statewide report. Two people on the train and a person in the dump truck were killed, authorities said Monday. As many as 50 people were also injured in the disaster, which toppled eight rail cars over, prompting a massive emergency response. The state report, issued in February as part of the Missouri State Freight and Rail Plan, listed the cro…