Laser monitoring to detect potential collapse

9:29am Sunday 28th August 2005

A LASER will monitor the Tesco tunnel to detect a potential collapse and warn off trains.

The laser monitoring system has been put in place which will electronically alter train signals if any movement is detected.

Seven weeks on from the railway nightmare of the Tesco tunnel collapse, experts have said it is safe for services to resume.

Network Rail executives confirmed the tunnel was safe for use by Chiltern Railways at a press conference, held at the Jacksons Engineering site office.

John Armitt, the chief executive of Network Rail, said: "The re-opening will be an extremely big relief for commuters. That has been our main priority since the collapse rectifying the situation so that trains can run again.

"We had to be satisfied that it was safe to run trains. We had to be fully confident. That has taken a few weeks I am afraid. The most important thing was to know that it was safe so that passengers can travel in confidence."

Limited passenger services resumed on early Saturday morning, with full commuter services getting back up to speed yesterday.

Since the collapse, on June 30, Tesco's contractors Jacksons has removed 63 metres of the 300 metre tunnel.

Around 8,000 tonnes of infill from the collapsed area and a further 7,000 tonnes from the side of the collapse have been taken away.

Roger Dickinson, the contract director for Network Rail, said: "All the remaining parts of the structure have been extensively and thoroughly examined and tested. The remaining structure is safe."

The Health and Safety Executive, which is still determining who is to blame, gave its full support to the move.

Mr Dickinson said: "The future of the superstore project is a matter for Tesco. Much more evaluation work is needed before any potential future work will be allowed on the remaining tunnel."

A spokesman for Tesco said: "Until now we have been concentrating on getting the railway open.

"Now we are taking stock before we make any decisions."