Union Pacific No. 4000

Union Pacific No. 4000 was a four-cylinder articulated 4-8-8-4 Big Boy-type steam locomotive owned by the Union Pacific Railroad. This locomotive was built by Alco in 1941 along with the other Big Boy locomotives to address the problems concerning the preceding 4-6-6-4 Challenger class locomotives.
It ran in service until July 1959, when it was retired along with the other Big Boy locomotives. It was sold for scrap.
==Trivia==
*No. 4000 was the prototype of the class.
*The 4-8-8-4 class series, originally rumored to be called the "Wasatch", acquired its nickname after an unknown worker scrawled "Big Boy" in chalk on the front of No. 4000, then under construction as the first of its class.
==Gallery==
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File:UP4000-1.jpg
File:Union Pacific No. 4000.mov
Category:Steam locomotives
Category:Tender locomotives
Category:American locomotives
Category:Union Pacific locomotives
Category:4-8-8-4 locomotives
Category:4-8-8-4 steam locomotives
Category:Articulated locomotives
Category:ALCO locomotives
Category:Built in 1941
Category:Scrapped locomotives
Category:Standard gauge locomotives
Category:Locomotives
Category:Prototype locomotives
Category:Scrapped steam locomotives
Category:Union Pacific Big Boy
Category:American steam locomotives
Category:Standard gauge locomotives of the United States