126-0401 FEF-3 Steam Locomotive Union Pacific 844The Union Pacific FEF (Four Eight Four), along with the GS 4 is easily one of the most recognisable US steam prototypes still in operation today. The FEF 3 series of steam locomotives was delivered in 1944 and were the last, and some of the largest, steam locomotives delivered for use by the Union Pacific. Operated solely by the Union Pacific, the FEF's (sometimes referred to as "Northerns", due to the NP's being the first to build steam locomotives