Scores of people have been killed or injured in Mexico City after a railway overpass collapsed onto a busy road below, and derailed a metro train in the process.The disaster happened at about 10:30 on Monday (May 3) night. Several children are among the dead. Worsening the disaster, rescue efforts had to be temporarily halted over fears the structure could collapse even further. At least two train cars were hanging precariously from it.They were trying to stabilize the structure using cranes.It’s not immediately clear what caused the tragedy. Mexico City’s mayor, Claudia Sheinbaum, said at the scene that it appeared a girder on the bridge had given way.The railway line is less than 10 years old.