Union Pacific No. 3900 (1936)

Union Pacific No. 3900 was a fetter 4-6-6-4 "Challenger" type steam locomotive owned by the Union Pacific Railroad.
Category:Union Pacific locomotives
Category:4-6-6-4 steam locomotives
Category:4-6-6-4 locomotives
Category:Tender locomotives
Category:Steam locomotives
Category:Locomotives
Category:Scrapped locomotives
Category:Scrapped steam locomotives
Category:Standard gauge locomotives
Category:Standard gauge locomotives of the United States
Category:Built in 1943
Category:ALCO locomotives
Category:Six-coupled locomotives
Category:Articulated locomotives
Category:American locomotives
Category:American steam locomotives
Category:Fetter Locomotives
Category:Prototype locomotives