RAIL passengers face delays for the next few weeks as speed restrictions are introduced on a stretch of the Swindon line where cracks have been found by Railtrack.

The company is to carry out ultrasonic tests on the track to the west of the station to discover how bad the problem is, and re-rail sections if necessary.

It has also decided to re-rail track at Pewsey this weekend which has been identified as problematic, along with sections of track at Didcot.

Passengers now face severe disruption. The work is expected to take weeks, during which a 20mph speed limit will be in force.

The area near the station was due to be re-railed in the next few years but after the Hatfield crash, in which four people died when a train de-railed on a piece of broken track, Railtrack decided to act sooner.

It brought in the restrictions yesterday morning and is now drawing up a programme to carry out the repairs.

Rail travellers are already experiencing delays after First Great Western imposed a speed limit on parts of the Swindon to London line at Didcot and also at Thatcham.

Jane Terry, spokeswoman for Railtrack, said the company was taking every precaution to show passenger safety is a priority.

"The patch of track in Swindon was showing signs of corner cracking, which is a bit like split ends in hair. It doesn't do any damage unless it is left for some time," she said.

"We have taken the decision to test the area and re-rail it if necessary. We have as many people working on it as possible but there is no time frame. It will take the next few weeks and the restrictions will stay until it is completed.

"Pewseyis one of the places creating a bit of a bottleneck for trains coming through from London to the West so we decided to concentrate on re-railing those areas and then on lifting the speed restrictions.

"Trains will go slower because there are quite a lot of speed restrictions along the track. First Great Western has issued an emergency timetable which is building in time lost because of the restrictions on the journeys.

"We would hope that by Monday we will have a better idea and review the timetable."