London’s Holborn underground station closed briefly Tuesday after overheating equipment on a train filled a platform with smoke.
The fire service said it had sent two fire engines and 10 firefighters to the station.
“It was an overheated compressor on a train not a fire,” London Fire Brigade said a statement.
A witness on a train at the station said smoke filled one of the carriages.
“There was a fire alert on a westbound Central line train,” a spokesman for London’s transport operator said. “We are investigating the cause.”
The fire service said it dealt with the incident in less than 50 minutes.