Originally Posted by Dennis LaGrua:
I believe that the UP Big Boys ran until 1962. Not sure about the C&O Big Boys. Steam was replaced by diesel, as it was just too costly to maintain and when diesel engines became more powerful. I guess the Strasberg RR would disagree as they still run steam for freight and passenger revenue service to this day.
The last revenue run of a Big Boy (4-8-8-4) on the Union Pacific ended on the evening of July 21, 1959, when 4015 brought a train over Sherman Hill from Laramie to Cheyenne.
C&O had no Big Boys. Their big engine was the H-8 2-6-6-6 Allegheny. They last ran in revenue service in 1956.