The deadliest Mexico City Metro accident in nearly 50 years, killing 26 people and exposing systemic failures in Line 12's design, construction, and oversight.
Key Facts
- Date and time
- 3 May 2021, 22:22 CDT
- Fatalities
- 26 deaths
- Injuries
- 98 people
- Line affected
- Line 12, Mexico City Metro
- Line fully reopened
- 30 January 2024
- Charges filed
- 10 former officials, December 2021
By the Numbers
Location
Cause → Event → Consequence
Line 12 suffered structural and technical problems from before its opening, compounded by a 2017 earthquake. Budget and scheduling pressures had led to design changes that introduced track instability. Inadequate supervision of construction, faulty welds, non-functional studs, and the absence of required periodic maintenance inspections left the overpass girder in a critically fatigued state.
On 3 May 2021, a girder overpass in Tláhuac borough carrying Line 12 of the Mexico City Metro collapsed under a passing train, dropping the last two railcars onto Avenida Tláhuac near Olivos station. The collapse killed 26 people and injured 98 others, making it the deadliest accident in the Metro's history in nearly five decades.
Investigations by DNV and city authorities concluded the bridge was designed and built without adhering to quality standards and lacked sufficient safety elements. Grupo Carso, at no cost, repaired the collapsed section, which was also reinforced alongside general line maintenance. In December 2021, ten former officials were charged with manslaughter, injury, and property damage, and remained awaiting trial as of May 2026.