N.J. Stat. § 48:15-28
Whenever any street railway or traction company shall change the location of its tracks or any part thereof in any street or public park to another part of such street or park, or from a private right of way proposed to be taken for street or public park purposes to a new location within the lines of any street or within the boundaries of such park, or from any street, public park or private right of way to a new location in another street, at the request of the body charged with the maintenance and repair of such streets or public park on or through which such tracks are located and to which such tracks shall be moved, the company so changing the location of its tracks and its successors and assigns may maintain and operate its tracks with the necessary appurtenances in the new location for as long a period as it had the right to maintain and operate the tracks in their former location at the time of the relocation.
No such change shall be made without first obtaining approval of the Board of Public Utility Commissioners.
N.J.S. § 48:15-28