National Docks Secondary

National Docks Secondary is freight rail line within Conrail's North Jersey Shared Assets Area in Hudson County, New Jersey, used by CSX Transportation. It provides access to the national rail network to maritime, industrial, and distribution facilities at Port Jersey, the Military Ocean Terminal at Bayonne (MOTBY), and Constable Hook as well as carfloat operations at Greenville Yard. The line is an important component in the planned expansion of facilities in the Port of New York and New Jersey. The single track right of way comprises rail beds, viaducts, bridges, and tunnels originally developed at the end of the 19th century by competing railroads.

The line is used to access the port at the Upper New York Bay, which lies east of those crossing the Northeast Corridor. It runs parallel to the New Jersey Turnpike Newark Bay Extension for most of its length and passes through a cut in the Hudson Palisades. It travels north-south on the east side of Bergen Hill and through a short tunnel crossing beneath the PATH rapid transit system. At its southern end trains cross Newark Bay over the Lehigh Valley Railroad Bridge to the Oak Island Yard in Newark. At is northern end the line travels through Bergen Hill via the Long Dock Tunnel and after passing under Tonnelle Avenue junctions with the Northern Running Track. At North Bergen Yard, the line becomes the River Subdivision. It is an alternate, or secondary, route to the Passaic and Harsimus Line across the Kearny Meadows for trains passing through the Port of New York and New Jersey.