An EMD TR5 (TRansfer) 'cow and calf' set undergoes routine maintenance at Union Pacific's Pocatello, Idaho yard on July 28, 1980. The two units, connected semi permanently by a draw bar, were built by EMD for the UP in Sept. 1951. In 1952, the entire fleet of eight sets (UP 1870-1877) were equipped with dynamic braking for helper service on Cajon Pass in California and on Cima Hill in Nevada (with the gear later removed). In 1968, the 1870-1872 were modified with 1400 gallon fuel tanks and air reservoirs relocated on top of car body for hump yard service. The 1871-1871B would be retired from the active roster on Sept. 30, 1982. The 1871 'cow' was rebuilt as the UP 1241 in the SW10 program, released on Sept. 30, 1982 and retired yet again on Oct. 7, 1996. The 1871B was scrapped by the Union Pacific in Omaha, Nebraska in Sept. 1982.