The yellow locomotive in the consist is an Railpower 6-axle (3-axle trucks (bogies)) RP20CD, with three 700 horsepower generator-engine sets, a.k.a "gensets", which produce up to 2100 horsepower (even though the gensets produce a total of 2100 horsepower, which would make the model designation 'RP21CD,' the engines used replaced the previous diesel engines used, which produces 667 horsepower each). It was probably built under contract for Railpower Industries by Norfolk Southern at it's Juniata (Altoona, PA) locomotive facility. It's yellow paint obviously shows that the locomotive is destined to be 'turned over' to Union Pacific (who ordered it) in Chicago (or somewhere else that Norfolk Southern connects to Union Pacific).