N.J. Stat. § 40:67-32
When the tunnel or tunnels or approaches shall be located upon any land other than a highway or street, or land which has been acquired by the municipality, and such land or any right or interest therein shall be necessary for the construction of such tunnel or tunnels or approaches the municipality may acquire said lands in fee simple, or any lesser estate or right therein, and the proceedings for the acquisition of such property shall conform to the proceedings provided by law for the acquisition of lands for the opening of such streets in the municipality.
The proceedings to ascertain the damages, if any, sustained by the owner or owners of lands fronting on such improvements by reason of the construction and maintenance of such tunnel or tunnels or approaches, shall conform as nearly as may be to the proceedings provided by law for ascertaining the damages sustained by the owners of property injured by the change of grade of a street where such street has been built upon since the establishment of a former grade.
N.J.S. § 40:67-32