Commuters fled in panic after a metal crutch fell onto the rails and sparked a sudden blaze.
The metal crutch dropped onto the rails, triggering an electric arc and dense smoke just as a train pulled in.
Flames and thick smoke filled the platform as the object short-circuited the live tracks.
READ MORE: Influencer 23 takes her own life on livestream with fans left heartbroken
Passengers on the arriving train scrambled for the exits amid the chaos.
Emergency crews then cut the power and rushed to clear the hazard.
The drama unfolded at Moctezuma Station on Line 1 of the Mexico City Metro on the night of Tuesday 20 October.
Metro director Adrián Rubalcava said: “The object caused an electric arc and release of smoke, coinciding with the arrival of the train at the platform.
“Everything is in order; we are working to remove the object.”
Officials confirmed the power was interrupted for around 20 minutes in zones C and D while specialist teams retrieved the crutch.
No one was injured, and train circulation returned to normal once the tracks were cleared.
The affected train was sent for a routine inspection as a safety precaution.
MetroCDMX issued a statement urging passengers to keep their belongings secure and respect the yellow safety line at all times.
They warned that metallic items such as umbrellas, walking sticks, keys and flasks can also cause short circuits on the 750-volt rails.
Staff members have recovered around 380 such objects from the tracks so far this year.
The authorities stressed that anyone who drops something onto the lines must alert staff immediately and never attempt to retrieve it themselves.
Officials said the rapid response prevented any injuries to fleeing passengers.
READ MORE: Mum jailed for 25 years after injured daughter 12 died without treatment
