Sand Patch Grade is a ~100 mile length of railroad track known for its steep grades and curves through the Allegheny Mountains of Pennsylvania and Maryland.[1] The line is part of the Keystone Subdivision, an East-West main line operated by CSX Transportation. The line was originally built by the Baltimore & Ohio Railroad (B & O), which became a component of the Chessie System in 1972, then was merged into CSX in 1987. A well known landmark along Sand Patch Grade is the 4,475 foot Sand Patch Tunnel, which was constructed in the mid 1800's. Originally one track, the tunnel was expanded to two tracks in 1914. The tunnels used vertical ventilation shafts with fires in them to circulate air. The original tunnel was abandoned in 1917 and is now flooded and collapsed in places.[2] Dropping over 1000 feet in about 20 miles, Sand Patch Grade is one of the steepest railroad grades on the East Coast.[3] In 2001, the 'SA' Tower, one of the last manned interlocking towers was decommissioned and demolished. Mance, Pennsylvania, along the Sand Patch Grade is a popular spot for railfans and photographers due to the horseshoe curve located there, as well as the scenic backdrop provided by the old general store and tree farm. Also to watch the trains struggle up the steep grade, which is as much as two percent.[4]