N.J. Stat. § 48:3-38
All applications shall, in the first instance, be made to said superintendent. The superintendent shall investigate and determine the character, competency, integrity and fitness of the person or persons designated in the application. Notwithstanding any other provision of law in the case of any railroad, street railway, canal or steamboat company, the operations of which extend from this State to any other, such person or persons need not be residents of the State of New Jersey. If the application is approved by the superintendent, the applicant shall then present the approved application to the Governor.
Every person so appointed and commissioned shall, in the several counties, possess all the powers of policemen and constables in criminal cases of the several municipalities in such counties and shall be compensated by the company.
When on duty, except when employed as a detective, he shall wear in plain view a metallic shield or device with the words "railway police," "canal police" or "steamboat police" as may be appropriate, and the name or style of the company for whom he was appointed inscribed thereon.
Notwithstanding anything to the contrary herein contained, all appointments made prior to the effective date of this enactment which meet the requirements thereof shall be and they hereby are declared to be valid.
When any such company shall file in the offices of the Superintendent of State Police a notice that it no longer requires the service of such policeman, his power as such shall cease and determine.
N.J.S. § 48:3-38