Commuters waiting on a platform at Clapham Junction  after a power supply problem affecting the UK's biggest interchange station  led to scenes of chaos. Image by Josh Russell/PA Wire

Commuters waiting on a platform at Clapham Junction after a power supply problem affecting the UK’s biggest interchange station led to scenes of chaos. Image by Josh Russell/PA Wire

UK train travel on busy commuter routes has been plunged into chaos after a major power supply problem led to police and firefighters evacuating passengers stuck for hours in sweltering temperatures.

Water had to be handed out to stricken travellers, some of whom were still waiting to reach London more than five hours after boarding their train.

The problem, which was set to cause disruption throughout the day, was compounded by the fact that it affected Clapham Junction in south London – the UK’s busiest interchange station.

One passenger had to be treated by ambulance staff on one of the stationary trains, while firefighters used a short-extension ladder to evacuate travellers from one held-up service.

British Transport Police (BTP) reported evacuating 904 passengers from one train, while travellers on another stricken service were waiting for a tow.

Passengers spoke of “nightmare” conditions at Clapham Junction.

No Southern train company trains were able to get in or out of London’s Victoria station and there was no service on the Gatwick Express.

Passengers heading for London from southern England found they had to get off well short of their destination and travel in on other rail routes.

The unfortunate ones got stuck on trains unable to get through Clapham Junction.

One of the worst-affected trains was the 6.56am from Brighton which should have got into Victoria at 8.15am. Shortly after noon the train was still stuck near Clapham. One of its passengers student Hannah Phillips, 20, from Eastbourne, East Sussex, said: “I was lucky that I was carrying a bottle of water with me as it was getting very hot on the train.

Also on the train was Anna Roberts, a Press Association journalist. She said: “Police and paramedics boarded our train because there is no air conditioning. “Eventually we got water in plastic containers which we are passing around the carriage.”

The problem struck between Wandsworth Common and Clapham Junction in the middle of the morning rush hour.

A Network Rail spokesman said: “A major power supply problem between Clapham and Wandsworth Common has disrupted Southern train services into London Victoria this morning.

“Engineers are on site and we aim to resume services as quickly as possible.

“Tickets are valid on all other routes into London and Southern passengers are advised to avoid travelling through Clapham Junction, which is very busy.

“South West Trains services to and from Waterloo via Clapham Junction are unaffected.”

Those on the stricken 6.56am train from Brighton were finally towed to Wandsworth in south London, arriving shortly before 1pm.

National Rail information said that problems with the conductor rail between Wandsworth Common and Clapham Junction had caused damage to a number of trains.

Once the trains had been moved, repairs were likely to take up to three hours. Passengers were advised to avoid using Victoria station.

Shortly after 1pm Gatwick Express trains began running again but with delays.

(Press Association)