Big Boy was the nickname given to the Union Pacific Railroad's twenty-five 4000 class 4-8-8-4 steam locomotives built between 1941 and 1944 by Alco.

History of the 4017

The Union Pacific Railroad donated 4017 to the National Railroad Museum in July, 1961.

From 1961 until 2001 the 4017 sat outside, exposed to the harsh Wisconsin winters. As luck would have it, the Union Pacific took great steps to preserve the locomotive. They put a protective layer of a foam-like material in the firebox and in the smokebox to reduce the likelihood of rusting. They also applied two large covers over the massive smoke stacks. These efforts kept the innards of the beast well preserved, but the boiler jacket was not removed. Eventually the Museum had the boiler jacket removed. This decision protected the exterior of the boiler from severe rusting from constant water contact.

In 2000 the 4017 moved for the last time. 4017 is now placed indoors the Lenfesty Center at the National Railroad Museum.

External links

• Union Pacific Big Boys
• The Union Pacific 4017 website
• Big Boy main page at trainweb