What tunnel runs under the Hudson River and has a ventilation system innovated by Ole Knutsen Singstad?
Holland Tunnel The Holland Tunnel is a highway tunnel under the Hudson River between Manhattan in New York City and Jersey City, New Jersey. Its two tubes carry eastbound and westbound Interstate 78. In New Jersey, it is also designated NJ 139. An integral conduit within the New York Metropolitan Area, it opened in 1927 as the first of two vehicular tunnels under the river, the other being the Lincoln Tunnel. Both are operated by the Port Authority of New York and New Jersey.
Upper Hudson River Railroad The Upper Hudson River Railroad was a heritage railroad that operated from 1999 to 2010 in the upper Hudson River in New York State's Adirondack Mountains.