[citation needed] The line was opened between 1852[1] and 1856[2][3] by the Commonwealth of Pennsylvania as a bypass of a portion of their Allegheny Portage Railroad, itself a portion of the Main Line of Public Works.
Together with the railroad's Petersburg Branch, it was used as a bypass, providing a second route around the railyards at Altoona and the Horseshoe Curve on the mainline.
[5] In 1981, the line was abandoned from the east portal of the New Portage Tunnel to Hollidaysburg.
[6][7][better source needed] As of 2019, the New Portage Tunnel is still in use as part of Norfolk Southern's Pittsburgh Line.
The section from US 22 south to the Muleshoe Curve bridge over Old US 22 is a Pennsylvania State Game Lands road; the section from the Muleshoe Curve bridge to Foot of Ten, Pennsylvania is part of the 6 to 10 Trail.