THE Flying Scotsman will not be back on the tracks before 2015 - if ever, the National Railway Museum has revealed.

The York-based museum said an independent engineering report had identified substantial further repairs were needed to the iconic loco, at a substantial cost.

And a spokeswoman revealed that the viability of the whole restoration project might even be in doubt.

She said: “There is a small section of the main side frames that cannot be examined until the steam cylinders are removed by the appointed contractor.

“A final assessment of the viability of the restoration will be made once the condition of this final piece of the locomotive is known.”

The First Class Partnerships report suggests that the risks of any further serious problems are small and the cost of overcoming them, relatively low. However, we will only know the full picture a few months after works recommence, when the steam cylinders have been removed and we can undertake the detailed examination of the parts of the frames that are currently hidden.

There will be a break clause in the contract with the external contractor and we will review and agree the best way forward at that point.

The museum had decided it would not be sensible to complete the work in-house, and would go out to tender for an external contractor to carry out the work.

She said the report had recommended that the iconic loco’s middle steam cylinder needed realigning, requiring the removal of the boiler and all three steam cylinders.

“All three steam cylinders are also currently oversize and need to be fitted with new liners and rebored to a nominal 19 inch diameter,” she said.

She said the timescales involved with the tender, contract negotiations, the restoration work and testing mean that Flying Scotsman will not operate on the mainline before 2015.

She said she could not say how much the additional repairs were expected to cost. “We are unable to release the indicative cost in the First Class Partnerships report because this information is commercially sensitive,” she said.

“To release this figure would prejudice us being able to run a fair and competitive tender process, which could in turn impact upon our ability to obtain a contract that delivers best value.”

She said the museum had already spent £2.89 million on repairs to the loco, which were originally expected to cost only £750,000.

She said the report had been compiled by First Class Partnerships, which had been appointed last October to provide an independent review of the work required to complete the locomotive, indicative costs and timescales for the project and options for where the work should be completed.

Paul Kirkman, Director of the National Railway Museum, said: “It was vital that we really got to the bottom of this complex project and received independent verification of the problems associated with the locomotive and how best to complete the project.

“First Class Partnerships are highly respected in their field and provide the highest level of engineering consultancy. We have now clarified that it is not sensible to complete the work in house and are in a position to go out to tender for an external contractor.

“We will now progress cautiously towards completing the restoration, subject to reviewing the condition of the main side frames. We would like to take this opportunity to thank the public for their ongoing support and patience throughout this challenging project.”