A rogue cyclist caused rush hour delays in central London in Tuesday when he tried to ride his bike along the rails between Liverpool Street and Bethnal Green station.
Fifty trains were delayed and three cancelled outright while transport police officers pursued him over the open-air track.
The unnamed 31-year-old man made it more than half a mile before he was caught and arrested for trespass and obstructing the rails.
The cyclist was first spotted by a train driver, who saw him taking his bicycle down onto the track and immediately radioed the station control room to shut down the 25,000-volt wires humming overhead.
Station staff managed to snap a picture of him, wearing what appears to be a grey hoody and carrying a golf bag, before he pedaled off through the Bishopsgate Tunnel.
Officers then spread out across the track in search of the errant rider, but did not catch him until he had almost made it to the next station.
He was also spotted by commuter Jamie Walton, who said: Walking down the train line with a push bike and a set of golf clubs outside Liverpool Street, as you do!
Another commuter, Joseph Willits, was unfazed, tweeting: London is great. So many people in different accents and languages telling bosses theyre late due to drunk cycling trespasser at Liverpool Street.
Greater Anglia, which operates hundreds of services every day in north and east London and Essex, said the incident caused delays of up to 20 minutes and had knock-on effects on other services.
A spokesman for British Transport Police said he had no indication as to why the man had chosen to use a live rail track as a cycle lane.
He said: Our officers were called to Liverpool Street station at 9.22am on Tuesday, 19 August, after a report of a man cycling on the railway line.
Officers carried out a search of the track, assisted by staff from Network Rail.
A 31-year-old man was arrested for trespass and obstructing trains close to Bethnal Green railway station. The line was handed back to Network Rail at 9.49am.
