Union Pacific 4023

In the early 1940s, the Union Pacific Railroad designed the only simple articulated steam locomotive with a 4-8-8-4 wheel arrangement, which would be known as the "Big Boy" and would be the largest steam locomotive in the world. These locomotives began being constructed in 1941 by the American Locomotive Company in Schenectady, New York, and No. 4023 is one of the last five of these built in 1944. Just like all of its sister engines, No. 4023 was assigned for fast and heavy freight trains through the Wasatch Mountains and over Sherman Hill. Instead of being scrapped after its last run in 1959, No. 4023 was stored in the Union Pacific's roundhouse in Cheyenne, Wyoming[2] along with 4-6-6-4 Challenger No. 3985.[3] What might’ve likely been the reason for 4023’s mint condition to be saved for preservation is that it was given a class 3 overhaul in 1957.[4] In 1974, No. 4023 was cosmetically restored and towed to Omaha, Nebraska for static display in front of the Union Pacific's locomotive shops. After the locomotive shops were closed in 1988, No. 4023 was moved again to the Durham Western History Museum in Downtown Omaha.

In Spring of 2005, No. 4023 was moved by truck[5] on a highway[6][7] to a more permanent home in Kenefick Park[8] alongside an EMD DDA40X No. 6900.[9] During one of its cosmetic restorations, several functional appliances were replaced with new, mock appliances, including the safety valves, whistle, lubricators, and a new boiler jacket.

Today, No. 4023 is still on display at Kenefick, and with fellow Big Boy No. 4014[10][11] successfully restored to operation by the Union Pacific as part of their heritage fleet,[12] restoring No. 4023 is unlikely to happen anytime soon.