Are you sure that's the whole line? Various underwater tunnels in the
New York area are the "name Tubes", so the "Hudson Tubes" would
logically be the WTC branch with some other name for the 33rd Street
branch.

Yes, the entire Hudson and Manhattan Railroad was popularly known as
the Hudson Tubes. In fact, for a brief period after the H&M went
bankrupt, and before the Port Authority's PATH took over, the operator
was "Hudson Rapid Tubes".

I don't hear "Hudson Tubes" much any more; PATH seems to be the commonly
used name now.

Michael Wares