Actor Bill Paterson was among those who hoped the famous piece could stay as the studio contents of the artist's home in Gourock, Inverclyde went under the hammer last night.
The George Wyllie Foundation, featuring a large amount of his most important works, which will be formally launched next month, was privately hoping that whoever bought the piece would lend it back.
Wyllie, who died in 2012, aged 90, created the Straw Locomotive in 1987, the Paper Boat in 1990, and the Running Clock outside Glasgow's Buchanan bus station, and has been lauded as one of the most influential artists of the past 50 years.
The original Straw Locomotive, a full-scale rendition of a classic steam engine made from straw, which hung from the Finnieston crane for several months, was ceremonially burnt after it was taken down.
The ashes are now kept in a box by the Wyllie's family.
The metre-long version of the artist's original piece, sold for £14,500 to an unidentified buyer at the sale at the Lighthouse in Glasgow.
Wyllie had kept the small-scale locomotive in his studio after it was commissioned on behalf of the City of Glasgow.
Mr Paterson, a friend of the artist, who was at the sale suggested: "It could go to the Museum of Transport."
Wyllie admirer James Dickson, a private art collector who said he had contemplated buying the piece at the sale, said: "Really this is something that should be placed somewhere like the Burrell Collection as a lasting tribute to him."
It was standing room only in The Lighthouse as the 44 works, valued at £40,000, went under the hammer.