A man is alleged to have groped a woman on the Elizabeth line when trains were plunged into darkness on Thursday night.
Hundreds of passengers found themselves stranded on dark, cold trains for several hours by damage to overhead electric cables in the Ladbroke Grove area of west London at around 6.30pm.
Singer James Blunt and TV presenter Rachel Riley were affected by the disruption.
Jacek Broniszewski tweeted a video of a police officer telling frustrated passengers a man had been arrested and that they would soon be evacuated to the nearby North Pole Depot.
But British Transport Police said the male detained around 8.30pm was later released pending further enquiries.
The officer at the scene told commuters: “We haven’t just left you, I appreciate that’s… unfortunately we’ve had a few incidents. We’ve had one arrest of sexual touching and things like that.
“So things have taken longer than possibly what they should have done because someone decided that they wanted to touch someone up.”
Accompanying the video, Mr Broniszewski said: “Stuck on an Elizabeth line train for three hours, we were promised ‘buses and taxis’. All seemed like official protocol.
“After finally being let out, turned out there was no transport provided and we were stranded alone. Quite the mess. Also told of arrests for sexual touching.”
British Transport Police said on Friday: “While responding to the incident at Paddington station on December 7, officers on scene were made aware of reports of a sexual assault.
“The assault was reported to have taken place on the Elizabeth Line at around 8.30pm. A man was arrested and later released. Enquiries are ongoing to establish the circumstances surrounding the incident.”
The £19billion Elizabeth line – which opened in May 2022 – uses mainline rail infrastructure west of Paddington.
Paddington services have been repeatedly affected by rail system faults in recent weeks.
