The Downtown Hudson Tubes (formerly the Cortlandt Street Tunnel[2]) are a pair of tunnels that carry PATH trains under the Hudson River in the United States, between New York City to the east and Jersey City, New Jersey, to the west.

[7]: 15  The idea for the downtown tunnels was devised by another company in 1903, the Hudson and Manhattan Railroad Corporation (H&M).

However, William Gibbs McAdoo's New York and Jersey Railroad Company, which was constructing the Uptown Tubes, was interested in the H&M tunnel.

[14] That June, the New York State Board of Commissioners approved of the layout for the Downtown Tubes' Manhattan end.

[21] When the original World Trade Center was constructed in the 1960s, the Downtown Tubes remained in service as elevated tunnels until 1970, when a new PATH station was built.

[25] The last remnant of Hudson Terminal was a cast-iron tube embedded in the original World Trade Center's foundation, located near Church Street.

The cast-iron tube was removed in 2008 during the construction of the new World Trade Center,[26] a small section being donated to the Shore Line Trolley Museum along with one of the PATH train cars that were trapped underground when the towers collapsed.

The terror planners believed that Lower Manhattan could, as a result of the explosion, be flooded due to river water surging up the remaining tunnel after the blast.

If the tunnel were to explode and allow water from the Hudson River to flood it, Lower Manhattan would be spared since the area is 2–10 feet (0.61–3.05 m) above sea level.