SUPERMARKET GIANT Tesco has been told it will face a tough battle convincing Network Rail and Chiltern Railways that work can restart at the site of the Gerrards Cross tunnel collapse.
Full train services resumed on 22 August, almost a month after a 30m section of tunnel being built by Tesco contractor Jackson collapsed on 30 June (NCE 7 July). The tunnel was being built to create a site for a Tesco supermarket and car park.
But despite the Health & Safety Executive (HSE) declaring what is left of the tunnel safe, Network Rail and Chiltern Railways said that they are far from convinced that work should continue.
'Much more evaluation work is needed before any potential future work will be allowed on the remaining tunnel, ' said Network Rail contracts director Roger Dickinson.
'Tesco needs to continue investigations to demonstrate to Network Rail and others that what is left is good enough to be built on.
'This is no easy job for Tesco.
The process will be no less diligent than it was to allow the tunnel to reopen. They are working on providing this information and this will lead to future discussions on the site, ' he said.
Chiltern Railways said it would be 'some months' before a decision on the future of the tunnel is made.
'All safety assessments so far have been based around opening the railway through the existing sections of the tunnel.
No decision has been made on the future of the tunnel, nor will be made for some months, ' it said in a statement.
The HSE investigation into the collapse continues and is now focusing on a change made in the backfiling method two days before the collapse. Network Rail has already confirmed that the collapse was caused by overloading the crown of the tunnel (NCE 18/25 August).
'It was not a case of the rules being broken all the time, ' said Dickinson. 'There was a very clear point when the change was made and that is what the investigation is focused on now.'
To convince Network Rail and the HSE that the tunnel is safe, Jackson has removed 12,000t of fill from above the undamaged tunnel in addition to 15,000t from the collapsed area. It has also removed 34m of undamaged tunnel segments adjacent to the collapsed area.
'Tesco and its consultants have produced detailed analysis and substantial evidence and evaluation, independently checked by Atkins, that the remaining structure is safe, ' said Dickinson.
'But Network Rail, the HSE and its advisors will have to give approval for any future work to take place, ' he said.
Tesco said its priority had been to open the tunnel as quickly as possible, while being confident as to its safety.
'During this period we have not continued with work on the store itself. We are taking this one step at a time and are taking stock of the situation. Everyone is working together to find the right long-term solution, ' said a spokesman.
Network Rail chief executive John Armitt offered one possible long term use. 'What happens next is a matter for Tesco.
Do you leave what's there- Or do you convert it into something else- Our station car park gets full very quickly, ' he said.