The Union Pacific Railroad (reporting marks UP, UPP, UPY), legally Union Pacific Railroad Company and simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over 32,200 miles (51,800 km) routes in 23 U.S. states west of Chicago and New Orleans.
The Union Pacific Railroad system is the second largest in the United States after BNSF and is one of the world's largest transportation companies. The Union Pacific Railroad is the principal operating company of the Union Pacific Corporation, both headquartered in Omaha, Nebraska.
Founded in 1862, the original Union Pacific Rail Road was part of the First Transcontinental Railroad project, later known as the Overland Route.
Union Pacific has owned some of the most powerful locomotives. These include members of the Challenger-type (including the 3985), and the Northern-type (including the 844), as well as the Big Boy steam locomotives (including the 4014).
Union Pacific operated the largest fleet of gas turbine-electric locomotives (GTELs) of any railroad in the world.
The Union Pacific GTELs were a series of gas turbine-electric locomotives built by Alco-GE and General Electric between 1952-1961 and operated by the Union Pacific Railroad from 1952 to 1970.
According to en.wikipedia