The 849-foot Pinkerton Tunnel whisks travelers through the Pinkerton Horn, a hilly and narrow peninsula formed by a hairpin bend in the Casselman River, and is flanked on both ends by the Pinkerton High and Low Bridges. Originally built to carry the Western Maryland Railway, it was rehabilitated and reopened to bicycle and foot traffic in 2015. The corrugated liner is unique along the Great Allegheny Passage. The tunnel is wide, but not lighted, so take caution when entering. Travelers can explore a 1.5 mile trail that circumnavigates Pinkerton Horn and bypasses the tunnel.
The Western Maryland Railway constructed this tunnel in 1911 adjacent to a tunnel built for the competing Baltimore & Ohio Railroad. Railroad workers reported that the side-by-side tunnels made it sound as if a “ghost train” was in your tunnel when a competing train was only a few feet away behind a wall on the other line. The Western Maryland Railway’s tunnel was abandoned in the 1970’s and was further endangered by debris when the top of the B&O tunnel was removed to allow for double-decker container cars. The Great Allegheny Passage Conservancy led a subsequent repair-and-stabilization project to preserve and reopen the tunnel.