A FUNDRAISING campaign was launched today to bring one of Britain's most famous steam locomotives back to our railways.

The National Railway Museum (NRM) in York needs £250,000 to complete its restoration of the Flying Scotsman, which was bought for the nation in 2004.

The ''Steam Our Scotsman'' appeal will invite members of the public to sponsor vital elements of the engine's overhaul, from an outer firebox worth £100,000 to £25 for an individual bolt.

Andrew Scott, director of the NRM, said: ''Flying Scotsman represents the apex of British engineering and the romance of steam for the general public, and therefore it is important we bring her back to the main line for everyone to enjoy.''

He continued: ''We are hoping the people that helped us to save the most famous of locomotives back in 2004 will now pledge their continued support, and also that our quest to bring Scotsman back to Britain's tracks will strike a chord in a new generation of enthusiasts.''

The Flying Scotsman was built in Doncaster in 1923, at a cost of £7,944, to run on the route between London King's Cross and Edinburgh Waverley, a journey of 10-and-a-half hours.

It found its way into the nation's heart through a series of records, including the first non-stop London-Edinburgh journey and, in 1934, it became the first steam train to reach 100 miles per hour.

Mr Scott said: ''If you look at the story of this engine, it's always been in the public eye.

''From the minute it was built in 1923, it's always been the most powerful locomotive in the country. It caught a huge amount of attention.''

He continued: ''Like the Cutty Sark, like Concorde, it is one of those icons of transport history that is always in the public imagination.''

The locomotive remained in service until 1963, when it was purchased by a private buyer.

In 2004, the NRM's successful bid to save the Flying Scotsman included £415,000 raised by the public, and £365,000 donated by Sir Richard Branson, as well as a £1.8million grant from the National Heritage Memorial Fund.

After its purchase, it ran for two years on the main line, and, since 2006, specialists at the NRM's workshop have worked to overhaul the engine, but restoration costs escalated due to the condition of its boiler.

Jim Rees, curator of rail vehicles, said: ''Too often, financial constraints lead to the use of 'short-term fixes', with locomotives being repaired with no more foresight than the next seven or 10 years of certification; the very opposite of our own aims and ambitions for the Flying Scotsman.

''When the museum acquired the engine, it was carrying a boiler called the A4 (this was commonly done in British Rail days) that it had been fitted with in the 1970s.

''It also came with an A3 boiler that it had carried from 1964 until that date.

''The A4 boiler was in poor condition, having had many repairs and alterations, some conventional and recorded, others less so, so we decided to repair the A3 boiler, not just for the short-term, but to the highest possible standard.''

Despite fears over the economy, the restoration team remain hopeful the public will donate funds to push the overhaul forward.

''Of course these are difficult times, and £250,000 is a lot of money,'' Mr Scott said.

''But if we can just get that last mile down what has been a long road to undertake this rejuvenation of a locomotive, then the benefit, the promise of the engine being back in the public eye next year, I hope people will respond to.''

He said the NRM hoped the engine would be running on main lines again by the summer of 2010, after beginning testing early in 2009.