|Big Boy Duochrome|
Offered and noted at 30 Oct 2015, 16 Feb 2016 and 25 May 2016.
Offered and noted at 2 Nov 2019 and 3 Dec 2019.
| The Big Boys were one of the biggest steam engines ever built and the only locomotives to utilize the 4-8-8-4 wheel arrangement. 25 of them were built for Union Pacific, intended to haul heavy freight trains over the long and relatively steep grades of the Wasatch Mountains in Utah. They were designed with stability at 60 miles per hour (100 km/h), reliability and safety in mind.|
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