A section of railway closed by a 350,000 tonne landslip in January has reopened.
It was originally thought the stretch of the Chiltern Line between Leamington Spa in Warwickshire and Banbury in Oxfordshire would be out of action until Easter.
But the cutting was secured and made safe three weeks ahead of schedule.
The landslip happened at Harbury Tunnel on the route that runs from Birmingham to London Marylebone.
Network Rail said the cutting had been affected by landslides since it was built in the 1840s.
The route, which is used by 130 freight and passenger trains each day, resumed on 9 March.
What is a landslide?
- Landslides happen when the water in the ground forces the grains of the soil apart so that the grains no longer lock together and the slope does not have enough strength to stand up, so begins to slip downhill
- Their frequency is strongly related to the weather and long wet periods often result in a lot of landslides
- Once landslides start moving, they leave the slope permanently weakened and therefore can be reactivated
- Strengthening the slope can involve getting water out of the slope by drainage, or by adding stronger materials, such as steel rods or soil nails, to the slope.
Source: Dr Bill Murphy, senior lecturer in engineering geology at the University of Leeds
Passengers said the reopening was a relief.
"Having to spend all that extra time travelling has been a huge drain so we're really, really pleased it's back again," said one.
"I'm really excited the trains are running again," said another.
Network Rail said the cost of the clear-up operation would be "several million pounds".