The Harpers Ferry Tunnel, situated in the Harpers Ferry National Historical Park and the Chesapeake and Ohio Canal National Historical Park, was a critical component in CSX Transportation’s (CSXT) National Gateway Initiative (NGI) Phase 2. The goal of the NGI is to enhance clearance for double-stack trains, enabling them to reach the Mid-Atlantic East Coast ports in Maryland. To achieve this, clearance improvements were necessary for the historic Harpers Ferry Tunnel, built in 1894 and located across the Potomac River from the town of Harpers Ferry.
NGI Phase 2 was a progressive design-build program led by the Clark/Parsons joint venture. Delve Underground was the designer of the tunnel liner modifications, including grouting, arch liner removal, and liner notching. Construction of the tunnel improvements was subcontracted to a specialty tunnel contractor approved by CSXT. Construction inspection during tunnel modifications was performed by Delve Underground, with construction management provided by Clark Construction.
The project presented several unique design and construction challenges. These included restricted access and work windows due to heavy freight train and commuter rail traffic in the tunnel. The tunnel liner varied in age and materials, including a highly visible bell-mouth west portal constructed in 1931. In certain areas, bedrock was expected to be close to the tunnel liner, necessitating possible rock removal for clearance purposes. Additionally, minimizing disruptions to the Harpers Ferry community was a priority, and modifying the west portal required approval from the National Park Service.