Lemoyne was a significant location in the Harrisburg Terminal as early as the 1830s. Site of a strategic junction between the Northern Central and Cumberland Valley Railroad, the facility was located on the eastern edge of the small borough directly west and across the Susquehanna River from Harrisburg. Located approximately 2.5 miles south of Day Tower and Enola Yard, the original junction at Lemoyne was a physical crossing of the two railroads protected by an interlocking tower know as J (later Lemo). When the PRR assumed control of the two lines in late 1800's connecting tracks in the northwest, southwest and southeast quadrants were added to allow movements in a number of directions on and off the Northern Central, Cumberland Valley and into Harrisburg Station via the Cumberland Valley Bridge.
During the Cassatt Administration construction of the Atglen and Susquehanna, a rebuilding of the Northern Central and construction of the Enola Yard brought significant changes to the Junction at Lemoyne. With an effort to maintain lines that were free of interruption particularly at grade crossings with other busy railroads, the York Haven Line between Wago Junction and Enola was built closer to the river at a lower elevation, bypassing the intersecting lines and passing beneath the Cumberland Valley Bridge. In 1937-38 electrification brought about more changes at the junction with the Low Grade, Cumberland Valley Bridge and original NC alignment receiving catenary. What evolved from the years of change was a junction equipped with a kind of local and express lanes. The junction utilizing the quadrant tracks at the original location to move trains off the Cumberland Valley to Enola, Columbia and Harrisburg while the low grade routed trains around the junction all-together.
With the demise of passenger service on the Cumberland Valley in 1961, Lemoyne saw mostly freight activity with the exception of passenger trains off the Northern Central from Baltimore and Washington. These were often combined at Harrisburg with trains on the mainline from Philadelphia and New York City to head west, a practice that occurred into the Penn Central Era to a limited degree. In 1972 Hurricane Agnes pummeled the Northeast washing out a number of Penn Central properties including the Northern Central route between Wago and Baltimore. Since the line was primarily used for passenger and local freight traffic, it was deemed surplus and not rebuilt by the cash starved PC ending any regular passenger traffic through the junction at Lemoyne. Further loss took place under Conrail with the consolidation of Reading and PRR mainlines to Hagerstown. Compounded by the separation of Amtrak and Conrail operations and Conrail’s rebuilding of the Reading line to Harrisburg the existing Reading branch to Shippensburg provided an ideal connection for the project. The Cumbeland Valley route would be cut back to Carlisle with other segments incorporated into the new route that Conrail would later transfer to Norfolk Southern in 1999. Though not a through route, the old Cumberland Valley is a very busy operation today servicing a number of major industries between Lemoyne and Mechanicsburg with a yard and local crew base operating in Shiremanstown. All that remains at the junction at Lemoyne is the northwest connector to the CV and a few lone catenary poles with all Norfolk Southern traffic utilizing the low grade to the East.