The Glasgow-built engine was rescued from dereliction after being sent to Turkey for service in the Second World War.
A £120,000 appeal by the Scottish Railway Preservation Society (SRPS) to buy the near-complete locomotive is already nearing the half-way mark.
Initial restoration has started, but another £250,000 is required to complete the job.
Other steam locomotives in Scotland have either been refurbished for display in museums, such as a giant engine built for South Africa at the Riverside Museum in Glasgow, or acquired by heritage lines while still in working order.
The project comes as new ScotRail operator Abellio plans to expand steam services after initial runs to the Highlands in June, using SRPS coaches.
Further trips will operate on the Borders Railway when it opens next month. The SRPS said the locomotive once restored could haul trains on the line in the future.
Experts said the 73-year-old Stanier class 8F freight engine, number 45170, was in very good condition thanks to Turkey’s arid climate.
It also had its boiler rebuilt prior to being put into storage in 1986 when the country stopped running steam trains.
The SRPS said that should prevent similar problems to those which have hampered the restoration of the locomotive Flying Scotsman, whose boiler damage caused significant delays and cost increases.
The new SRPS engine, built by the North British Locomotive Company in 1942, was of a class which hauled coal trains for the London, Midland and Scottish railway, around places like Grangemouth.
It was among those gifted to Turkey in 1943 in an attempt to help maintain its neutrality against German influence.
The locomotive was bought and returned to the UK five years ago and displayed at the National Railway Museum’s Shildon site near Darlington.
The SRPS acquired it last year after its owner abandoned his own restoration plans.
The locomotive is on show at its centre at Bo’ness, near Falkirk, which has Scotland’s largest railway collection.
The SRPS said £54,000 had been raised to buy the locomotive over the last nine months, largely from its members, but it might chip in the rest once the total topped £70,000.
The society said that would be an important milestone because current restoration is limited to cosmetic work, such as repainting and polishing.
Mark Ashmole, an SRPS director and member of the project team, said: “This will be the first locomotive to be restored and returned to service in Scotland.
“It is tatty and has been bashed very hard in its life, but normally when you buy locomotives they have been stripped of everything and there is only a skeleton left. But this one was virtually complete.
“The Turks set aside the locomotive to be restored for charter work, when its boiler was rebuilt. It is in exceptionally good condition.”
A ScotRail spokesman said: “It’s been exciting to work with SRPS to successfully run our first-ever steam trains. There’s already a fantastic buzz about the 17 steam services we’ll run on the Borders Railway with SRPS – and we wish them all the best with their efforts to restore the locomotive.”