IT LOOKS like the results of a child’s fit of temper with a train set, distorted rails snaking away into the distance and a gap where track no longer meets up.

But this is a real-life railway, the Cotswold Line between Oxford and Worcester, where work is under way this week on the £10m first phase of a £62m project to reinstate double track on much of the route.

The wobbly rails were between Ascott-under-Wychwood and Charlbury in west Oxfordshire where engineers have just two weeks to move the existing single track across to one side along much of a four-and-a-half-mile section, install new drains and move signals and cables out of the way, so the extra rails can be laid next year.

By Monday, the tracks will have been straightened, rewelded and signal cables reconnected, so trains can run again from Oxford as far as Moreton-in-Marsh in Gloucestershire, Passengers travelling on to the western end of the line will have to change to a bus at Moreton before joining another train at Evesham, in Worcestershire, for the next few weeks.

The reason for this can be found underground near the picture-postcard Cotswold town of Chipping Campden. Surveying the route in the 1840s, the legendary engineer Isambard Kingdom Brunel chose to carry the line down from the Cotswold hills to the Vale of Evesham through a tunnel.

This 157-year-old structure is the focus of work this summer, with a 130-strong team of engineers working around-the-clock, with just six weeks to renew the railway inside.

Once the last train had run on July 17, engineers began to take out the existing single track and 20,000 tonnes of stone chippings that supported it. Much of the stone will be cleaned and reused.

Once new drains are laid and 50,000 tonnes of fresh stone is in place inside the tunnel, 14,000 sleepers will be brought in to support new rails.

The tunnel will be the only section of the route that gets new double track this summer, with eagle-eyed passengers able to catch a glimpse of it protruding at either end from September.

Network Rail structural engineer Natasha Luddington said it made sense to carry out all the work inside the tunnel at one go, although it meant there would be some short-term disruption for passengers.

She added: “There’s not enough room in here for us to work safely while there are trains running and it would be impossible to do this kind of work at weekends, bit by bit.”

The remaining 20 miles of new track will be laid next year, with much of the work carried out while trains are still running or overnight, to minimise disruption, creating a 32-mile central section of double track.

The nine miles between Charlbury and Wolvercot junction, north of Oxford, will remain single track for the time being, along with another section at the Worcester end of the 50-mile line.

But resignalling at both Oxford and Worcester, due in the middle of the next decade, could present an opportunity to complete the redoubling.

Trains will use the extra track from February 2011, with a new timetable expected to be introduced later that year.

David Northey, one of the Network Rail managers overseeing the project, said: “What we’re doing here is bringing back part of the railway.

“Once everything is in place, we will see improved performance on the route, with a more flexible railway, speeded-up journey times and capacity for extra trains, without the bottlenecks caused by the single-track sections.”

Train services between Oxford and Moreton, and Evesham and Worcester, will resume on Monday and operate until August 23, with buses replacing trains between Moreton and Evesham while engineering work goes on in Chipping Campden tunnel.

The whole line will then close again for another week, with a full train service resuming on Tuesday, September 1.