ENGINEERS from a Bury firm are on track to get the iconic Flying Scotsman back on the rails as part of a £4 million restoration project.

Riley and Son Ltd is currently involved in fitting equipment needed for the steam locomotive to operate on the main lines - with trials set to begin before the end of this year.

The overhaul of the famous engine began after it was bought for £2.3 million by the National Railway Museum, in York, in 2004. It is said to be one of the most complex restorations of a locomotive ever undertaken.

The Bury company, which is based at the locomotive works in the town's Baron Street, is carrying out work to fit the train monitoring recorder and the train protection and warning system.

Riley's co-director Colin Green said: "We have come through all the critical milestones for a locomotive restoration and although there is a lot of work still to get through and parts to fit, there is nothing significant standing in the way of Scotsman coming back to steam."

Several years ago, Riley and Son was appointed to complete the high-profile restoration project to bring the locomotive, which was built in Doncaster in 1923, back to Britain's tracks. And in 2011, the Bury Times reported that Riley and Son had been restoring the steam locomotive's boiler.

Bob Gwynne, curator of collections and research at the National Railway Museum, said the Flying Scotsman's inaugural main line run from London to York is scheduled to be the opening event for the museum's February Flying Scotsman Season.

He said: "The fitting of the equipment for the mainline really makes its return a reality. We still anticipate that the restoration work to return Flying Scotsman to steam will be completed in late 2015. This will be followed by a full programme of running in tests on heritage lines.

"Once it has built up sufficient mileage on the mainline — 1,000 miles under its belt —- and it's resplendent in its new BR green livery, it will be ready for its long-anticipated inaugural run between London and York. A triumphant return home at long last."

A commercial partnership agreement has been reached under which Riley & Son Ltd will manage the operation of the locomotive for the first two years of its new life.

This will include a programme of ongoing maintenance using Riley's experience of keeping steam locomotives on the tracks and in-depth knowledge of Flying Scotsman, as well as helping to resolve any issues that may arise during its return to mainline steam.

The locomotive, designed by Sir Nigel Gresley, was originally built in Doncaster for the London and North Eastern Railway (LNER). In 1928, it hauled the first ever non-stop London to Edinburgh service, reducing the journey time to eight hours. And, in 1934, Flying Scotsman was clocked at 100mph — the first locomotive to have reached that speed.