This was the actual locomotive that inspired the story- the Pere Marquette 1225. It was one of several N-class 2-8-4 locomotives built by Lima Locomotive Works in 1941, and one of only two remaining examples today. This locomotive was sold for scrap in the '50's, but saved and put on display at Spartan Stadium. That's where Chris Van Allsburg saw it, and was inspired to write the story "The Polar Express". Actual sound recordings of its horn were used in the movie based on the book. I got to see it come through Ashley, Michigan this year. Quite an impressive machine.