London's Victoria Tube station was evacuated earlier following a reported bang on a "faulty" train.
Eyewitness Ben Roe, 24, who was on the train, said he heard a bang and saw smoke under the train.
He said: "People were absolutely terrified. People were tripping up over each other as they ran up the stairs."
Transport for London said there were problems with a District line train due to faulty brakes and apologised to passengers for the "inconvenience".
'Loads of smoke'
London Fire Brigade sent three fire engines to the scene from 1603 BST until 1617 BST.
The Tube station reopened at 1645 BST.
Mr Roe said: "The train was coming into the station when there was a big bang. There was loads of smoke.
"Everyone was jumping off the train and running.
"We were told to get out of the station by any exit possible."
British Transport Police said there had been an "engineering issue" with the train.
The Tube train has been moved to Mansion House depot in central London.