By the late 1950s, with its P5a fleet aging, the Pennsylvania Railroad needed new electric freight locomotives. In fact, the PRR had never really had a successful electric freight locomotive. The P5a was originally built to haul passengers, being bumped from that duty by the more powerful GG1. The GG1s were best at hauling passenger trains; while also adequate for fast, time-sensitive freights, they were not as efficient on heavy freights (especially coal and ore trains), at a time before roller bearings were widely used on freight cars. The PRR had purchased E2b, E2c, and E3b demonstrators, but was not particularly impressed, for a variety of reasons. The railroad even considered complete freight dieselization, and commissioned studies on this from builders Alco, GM's EMD and General Electric; however, all three builders recommended retaining all existing electrification and acquiring new electric locomotives. The PRR took special note of twelve state-of-the-art EL-C electrics built by GE for the Virginian Railway, who was satisfied with their performance on their coal trains in the Blue Ridge Mountains. The PRR then approached GE about building a similar locomotive, resulting in an order for 66 such units in 1959.