Years of Unheeded Warnings. Then the Subway Crash Mexico City Had Feared.

Mexico City’s subway system has been plagued with problems for years. On Monday, an overpass collapsed, and the newest subway line plunged some 50 feet, killing at least 24 people and setting off a political firestorm.

MEXICO CITY — The capital had been bracing for the disaster for years. Ever since it opened nearly a decade ago, the newest Mexico City subway line — a heralded expansion of the second largest subway system in the Americas — had been plagued with structural weaknesses that led engineers to warn of potential accidents. Yet other than a brief, partial shutdown of the line in 2014, the warnings went unheeded by successive governments. On Monday night, the mounting problems turned fatal: A subway train on the Golden Line plunged about 50 feet after an overpass collapsed underneath it, killing at least 24 people and injuring dozens more.