It was bought by an online bidder on thesaleroom.com at Worcestershire specialist saleroom GW Railwayana Auctions on November 17, estimated at £30,000-35,000.
The auction included more than 500 attendees, along with a lot of bidders on the phone, internet and in the room.
The previous railway engine nameplate record was the £60,000 paid for a Golden Fleece nameplate in 2004, which was offered at Sheffield Railwayana Auctions.
Despite the status of the Flying Scotsman, built in Doncaster 1923 for the LNER, it has experienced a complicated history since being retired from regular British Rail service.
In 1996 it was sold to the late Dr Tony Marchington. Following a bankruptcy, in 2003 both original nameplates and workplates were sold into the railwayana world and the loco was fitted with reproductions.
The 1.47m (4ft 10in) long Flying Scotsman plate, from the right-hand side of the engine, was consigned to this latest auction by the family of a collector. It was the first time either nameplate has been on public sale.
GW Railwayana director and auctioneer Simon Turner said: “The other original nameplate lies in a large collection, so it highly unlikely that it will reach the railwayana market.”