N.J. Stat. § 48:12-51
When the tracks of a railroad company shall cross a highway, such highway may be carried under or over the tracks as may be found expedient.
Where an embankment or cutting shall make a change in the line or route of the highway desirable with a view to a more easy ascent or descent or where more land is required to make an embankment or cutting in the highway in its approaches to the crossing to adapt it to the grade thereof, the company may acquire by purchase or condemnation, such additional land for the construction of the crossing of such new line or route or elevation as it may deem necessary.
Such land, when so acquired, shall become a part of the highway in the same manner and by the same terms as the adjacent parts of the highway are held for highway purposes.
N.J.S. § 48:12-51