 Once the electrification project had reached Penrith in October 1955, 4501 had its first opportunity to haul passenger trains.Six months later, when the first 46-class arrived, the locomotive became a regular assistant locomotive for steam powered trains on the Main North line between North Strathfield and Hornsby.In 1957, it was transferred to the Flemington Maintenance Depot where it was employed as a shunter.