Two injured as train derailed by landslide near Watford Junction
Two people have been hurt as a train derailed near Watford Junction after striking a landslip caused by torrential rain.
The 6.19am London Midland service from Milton Keynes to London Euston came off the track at around 7am.
Another train travelling in the opposite direction "gave a glancing blow" to the derailed train, Network Rail (NR) said.
East of England Ambulance Service said a man was treated for a neck injury and a woman for chest pains.
Their conditions were not thought to be serious or life-threatening, a spokesman added.
The incident caused major delays to services and London Midland warned passengers to avoid travelling to or from London Euston, the sixth busiest station in Britain.
Martin Frobisher, route managing director for Network Rail, said a train hit a landslip, resulting in a small section of the train leaving the tracks a few miles north of Watford. The train remained upright, he added.
"Engineers are on site and train services are now running through the area but it will be some time before a normal timetable resumes," he said.
Initially, all four lines of the West Cost main line were closed at the scene, but two were reopened at around 8am.
Mr Frobisher added: " Our priority is to fully reopen the railway as soon as it is safe to do so. A full investigation into what happened will take place."
A London Midland spokesman said: "We can expect disruption until at least the afternoon so the advice is not to travel to or from Euston this morning and check for further updates later today. London Midland train tickets are being accepted on alternative routes."
Radio reporter Sarah Lowther, who was on the derailed train, said two trains were "kissing each other" in a tunnel.
She spoke of a "Dunkirk spirit" on board as passengers helped one another, but said she was worried about the driver, who had a bad back after the crash.
Speaking to Morning Money radio, she said: "The trees were taken down from the side of the rail line last year. Trees have roots, roots hold the mud. The mud had nothing to cling on to.
"It was the first time I've actually flown on a train; when we came off the tracks I assumed the brace position.
"Everyone is looking after each other with water and sugar but we're worried about our driver."
A pregnant woman was on board who emergency services were trying to remove from the train, she added.
Ms Lowther got on the train at 6.47am at Berkhamsted, and it was hit by an "oncoming" train at 7.01am.
British Transport Police said officers were working with fire and ambulance services at the scene.
Passengers were advised to check www.nationalrail.co.uk for the latest updates on services.
Francis Thomas from London Midland told BBC Radio 4's Today programme the driver of the train "reported hitting something" which caused the train to derail.
"This is the busiest piece of railway that carries freight and passengers in the whole of Europe, it affects anything that goes to the West Midlands, to the North West and Scotland - all train services have been affected this morning, it will take quite a long time to get the service recovered," he added.
"We have got extra staff on site assisting those passengers (on the train) and that is our focus - to look after those passengers, make sure they are all right and get them to their final destinations."
Mr Thomas said trains go in and out of London Euston every 90 seconds, and that he expects disruption "until lunchtime, and possibly longer".