Union Pacific 4023 is a 4000 class 4-8-8-4 "Big Boy" type steam locomotive, preserved at Kenefick Park in South Omaha, Nebraska.

4023 was assigned for fast and heavy freight trains through the Wasatch Mountains and over Sherman Hill.

4023 was repainted to be put on display for that year's National Railway Historical Society Convention in Cheyenne, Wyoming alongside 4-6-6-4 "Challenger" No.

4023 was cosmetically restored and towed to Omaha, Nebraska, for static display in front of the Union Pacific's locomotive shops.

4023 was moved to the original Kenefick Park on Abbott Drive, near the former Union Pacific shop site.

4023 was moved by truck on a highway[4] to the new location of Kenefick Park,[5] where it was put on static display alongside EMD DDA40X No.