Union Pacific 3985

Union Pacific 3985 is a preserved "challenger"-type engine.

Biography
The engine was built in 1943 for use with heavy freight trains, but it did pull passenger cars later in it's career.

The engine was done with service in 1957, but officially retired in 1962. It remained on static display until people came by to restore it. The engine was officially restored in 1981 and has been in operation to this day.

The engine is credited to be the largest steam engine still in operation.