Charing Cross in London was thrown into chaos after a trespasser jumped onto the railway tracks.
Hundreds of commuters were evacuated after an alarm sounded at the station during rush hour.
Trains between London Bridge and Charing Cross were halted, and other trains canceled or diverted.
A photo circulating on social media showed a man wearing all black standing on a railway bridge over the River Thames.
Steve White, managing director of Southeastern Railway, said: “The trespassers have been removed from the railway and the entire line is now open to traffic.”
“We will strive to restore service as soon as possible.”
Crowds were seen outside Embankment, King’s Cross, Cannon Street and Victoria as staff tried to introduce a queuing system.
Police rushed to Charing Cross and several vans were spotted outside the station.
By 7 p.m., Southeastern Railway said the trespassers had been arrested and power to the line was back on.
One rail company suggested that major disruptions would continue until 8:15 p.m.
In addition to the Overground, delays also occurred on the Piccadilly, Victoria, Bakerloo and Central lines of the Underground.
South Eastern said in a statement just before 8pm: “Trains are operating between Charing Cross and London Bridge.”
“Unfortunately, due to high latency across the network, delays are expected until the end of service.”
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