Such certificate shall be produced and shown on request of the conductor or person in charge of the train on which such person is riding. Such presentation shall entitle the person to whom the certificate is issued to pass and repass without payment of fare in regular coach service on all railroads operating such passenger service in this State, within the borders of this State: provided, however, that no certificate shall be valid for passage on interstate trains which do not provide intrastate service, or on extra fare or special purpose trains.
N.J.S. § 48:12-111