Thousands of commuters were left stranded during the morning rush hour after a train lost power 400 yards from Belmont station.
Services were suspended between Epsom Downs and Sutton after the 9.09am Southern service to Victoria suffered an electrical supply failure.
Dozens of passengers on board had to be evacuated and walked along the tracks to safety.
This afternoon a Southern spokesman said: “The 09.09 Southern service from Epsom Downs to Victoria was stopped approximately 400 yards from Belmont station due to a power supply failure.
“We understand that this may have been due to a cable fire, but this has not been confirmed.
"The train is still stranded, but all passengers have been safely 'de-trained' and walked up the track to Belmont station."
A rail replacement service has been operating between the locations and Southern tickets were being accepted on S1 and 280 London bus routes.
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