This abandoned railway line was initially constructed in the 1850s by the State of Pennsylvania as the New Portage Railroad, to bypass the incline planes used on the Allegheny Portage Railroad. It was acquired and then abandoned by the parallel Pennsylvania Railroad (PRR) in 1857, since the PRR had opened its mainline through the area in 1854, and routed all traffic on its own route.

In 1904, this line was reopened by the Pennsylvania RR as a freight bypass route. To distinguish it from the other PRR mainline, named for its horseshoe curve, this line was affectionately called "The Mule Shoe Line". It remained in service through the Penn Central years (1968-76) and was abandoned by Conrail in 1981. Freight business had declined, and part of the route near Gallitzin was used for a realigned US Route 22.