Big Boy will be on display for the public on Thursday from 9 a.m. to 3 p.m. and admission is free. Metro Transit is offering free downloadable passes for easy access to Union Depot Thursday.

KSTP/Jonathan Yuhas

According to a release from Union Depot, the locomotive is 132 feet long and weighs 1.2 million pounds. It was retired in December, 1961 after logging over 1,000,000 miles, primarily hauling freight between Wyoming and Utah. Twenty-five Big Boys were built during the 1940s, with only eight remaining in existence. The only one that remains operational is No. 4014 — the locomotive touring throughout the Midwest.

The locomotive runs on recycled motor oil. All of its fuel is provided by Wayne Transport in Rosemount. They have a tanker that follows the train all over the country that refills it.

The locomotive left Cheyenne, Wyoming on July 8, kicking of its "Great Race Across the Midwest" tour with the Union Depot being one of the few stops. The tour will continue on to Wisconsin, Illinois, Iowa and Nebraska.