One woman died and at least two people were critically injured after a US metro train filled with smoke.
Amateur footage has emerged of the incident in Washington DC, showing passengers struggling to breathe.
Scores of people were evacuated, with 84 going to hospital, according to the District of Columbia Fire Department.
Passenger Denzel Hatch said: “The train shut down and there was a lot of smoke and people could barely breath. We had to be evacuated back through the tunnel but there was no electricity or visibility.”