The accolade for Flying Scotsman comes months before the engine will finally run again after an extended, decade-long restoration.
It narrowly beat the Rajadhani Express, the pride of Indian railways, and the Orient Express, to top the survey of more than 5,000 people in the UK, United States, Australia and India. They were asked to name five trains or locomotives they had heard of.
The National Railway Museum in York, which owns Flying Scotsman and commissioned the YouGov poll, had previously described it as “arguably the most famous locomotive in the world”.
The result was announced to coincide with the 81st anniversary of Flying Scotsman being the first locomotive to break the 100mph barrier.
The 92-year-old engine, which was bought for the nation in 2004, is due to be unveiled in February to make its inaugural run between London and York.
The former east coast main line express locomotive will return to Scotland in May for the first time in 16 years by hauling a train from York to Edinburgh and then travel over the Forth Bridge into Fife as part of a four-day tour from 14-17 May.
Completion of the £4.2 million overhaul will see Flying Scotsman becoming the oldest mainline working locomotive on the British network.
Designed by Edinburgh-born Sir Nigel Gresley, the Pacific class A1 locomotive was plucked from obscurity by the London and North Eastern Railway to front a new premium London-Scotland rail service in 1928 in an attempt to trump its west coast rivals.
The engine was given the same name as the long-established Flying Scotsman train to haul a non-stop service between the English and Scottish capitals.
However, the rebuild has taken much longer than expected, with costs rocketing from £1.5m, because far more extensive repairs were found to be needed than anticipated.
Museum director Paul Kirkman said: “Our survey, carried out across four global markets, backs up the claim it is probably the most famous locomotive and express train service in the world. We are thrilled to offer a unique opportunity to experience the essence of Flying Scotsman, first-hand at our museum, through a series of innovative and colourful exhibitions and events.”
UK heritage minster Tracey Crouch, said: “From early 2016, the Scotsman will tour the UK as a working museum exhibit, educating fans of all ages about the wonders of the engineering behind its steam traction.
“This is a wonderful way to tell the story of this iconic and well-travelled locomotive and will ensure that people now and in the future understand why it is such an important part of Great Britain’s heritage.”