The local Cargill grain elevator replaced their SW1 with a Trackmobile a few months ago, and donated the old locomotive to the Union Station Foundation, operators of the museum. Pictures of the locomotive can be found here:
Golden Spike R&LHS USRRM locomotives page
Cargill, as part of the donation, generously agreed to repaint and repair the locomotive. Sanding was completed by June 4th.
As an interesting side note, the locomotive is one of the first SW1s to be built, and in fact predates the official SW1 classification as it was built as an NS1.