23 dead as Mexico City metro overpass collapses onto road The collapse occurred on the newest of the Mexico City subwayâs lines, Line 12, which stretches far into the cityâs south side. Â Â Mexico City subway cars lay at an angle after a section of Line 12 collapsed in Mexico City on Tuesday. The section passing over a road in southern Mexico City collapsed Monday night, dropping a subway train and trapping cars. [ MARCO UGARTE | AP ] Updated 55 minutes ago MEXICO CITY â An elevated section of the Mexico City metro collapsed and sent the train plunging toward a busy boulevard late Monday, killing at least 23 people and injuring at least 79, city officials said.