JACKSON Civil Engineering is looking to begin rebuilding the collapsed Gerrards Cross tunnel in Buckinghamshire early next year.
The Ipswich firm and client Tesco are almost ready to submit their second approval document to Network Rail to allow reconstruction of the tunnel.
Jackson is the main contractor on a £20 million deal to build a tunnel over a 320 m section of track at Gerrards Cross.
Jackson was backfilling over the tunnel for the construction of a new Tesco store in June when a 30 m section of it collapsed onto the track, causing travel chaos.
Jackson managing director Richard Neall said: 'We are working with Tesco on getting agreement on the way forward and Network Rail is helping us with the approval document we have to submit.
'It's up to Tesco to decide on whether the project will go ahead but we have had no indications as yet to suggest anything otherwise.
'We would like to get this done as everybody has spent a lot of money so far.' Mr Neall ruled out an immediate start on tunnel repairs. Costain ? the firm which started works on Tesco's store ? has also been stood down.
He said: 'Tesco has got to make the call on the programme but we don't know how long Network Rail will take to assess our submission.
'With Christmas coming up the new year is looking more realistic in practical terms.' The tunnel section collapsed because too much fill was placed on top, and insufficient levels placed on either side. Jackson is now planning to use a lighter material as fill in rebuilding works.
Mr Neall said: 'There are likely to be tweaks in how we manage the backfilling process and the use of a lighter fill in certain areas. But we are talking minor adjustments rather than fundamental design changes.'