A rail line was left in chaos when a passenger train broke down and the rescue engine sent to fix it also failed.
The South Central train broke down at Fishersgate, west of Hove, bringing to a halt several trains further down the line.
The problem was made worse when the rail company sent another engine to help assist the stricken train only for it to break down as well.
Rail bosses were also forced to shut the west line for safety reasons when some passengers grew tired of waiting and decided to leave their carriages and walk.
The ensuing train jam went back as far as Angmering, causing misery for hundreds of passengers who had to wait more than three hours for the trains to be fixed.
Passenger Fiona McClymont, 31, was stuck on a South West train just outside Shoreham.
She said: "It ruined my evening. At one point we all had to huddle together in one carriage because they turned all the lights and heating off.
"The worse thing was that when the train finally got going again we were only 60 seconds away from the platform. We then had to organise a taxi to Brighton ourselves."
An ambulance had to be called for one woman who suffered from diabetes and had got into difficulties during the long wait.
A spokesman for South Central said: "All we can do is apologise profusely for the inconvenience caused on Saturday evening.
"We managed to re-direct some trains but there were long waits for many passengers.
"It was bizarre chain of events. The first train lost all power outside Brighton and then the train we called out to assist it also failed.
"We then had to shut down the other line as well because people were getting off the train and we had to cut all power from the track.
"These things don't happen very often but they do happen."
He said South Central passengers would be able to claim compensation for the delay to their journeys under the company's customer charter.
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