Pere Marquette 1225 is a class "N-1" 2-8-4 "Berkshire" type steam locomotive built in October 1941 for the Pere Marquette Railway (PM) by Lima Locomotive Works (LLW) in Lima, Ohio. No. 1225 is one of two surviving Pere Marquette 2-8-4 locomotives, the other being 1223, which was on display at the Tri-Cities Historical Society near the ex-Grand Trunk Western (GTW) coaling tower in Grand Haven, Michigan, and both have the distinction of being the only surviving Pere Marquette steam locomotives left in preservation. No. 1225 was well known to be the basis for the locomotive used in the 2004 film The Polar Express, earning itself the nickname "The Real Polar Express."

The Polar Express is a 2004 American animated adventure film directed by Robert Zemeckis, who co-wrote the screenplay with William Broyles Jr., based on the 1985 children's book of the same name by Chris Van Allsburg. It stars Tom Hanks, Daryl Sabara, Nona Gaye, Jimmy Bennett, and Eddie Deezen. The film depicts human characters using live action and motion capture computer animation, with production sequences for the latter taking place from June 2003 to May 2004. Set on Christmas Eve, it tells the story of a young boy who sees a mysterious train bound for the North Pole stop outside his window and is invited aboard by its conductor. He joins other children as they embark on a journey to visit Santa Claus, who is preparing for Christmas.