MEXICO CITY (AP) — An elevated section of the Mexico City metro collapsed and sent a subway car plunging toward a busy boulevard late Monday, killing at least 20 people and injuring about 70, city officials said. A crane was working to hold up one subway car left dangling on the collapsed section so that emergency workers could enter to check the car to see if anyone was still trapped. Mayor Claudia Sheinbaum said 49 of the injured were hospitalized, and that seven were in serious condition and undergoing surgery. Sheinbaum said a motorist had been pulled alive from a car that was trapped on the roadway below. Dozens of rescuers continued searching through wreckage from the collapsed, preformed concrete structure.