53 Pa. Stat. § 15554
It shall be lawful for, and the right is hereby conferred upon, cities of the first class of this Commonwealth, their assigns, lessees, and licensees, to connect the tracks or railways, acquired, constructed, owned, or operated under the rights conferred by this act, with the tracks of any railroad or railway company, upon such terms and conditions as may be agreed upon; and to contract with such company for the use of its tracks or for the interchange of cars, whether passenger or freight, for continuous movement over any such connecting tracks, upon such terms and conditions as the councils of such cities shall determine. Such cities, their assigns, lessees, and licensees, may use such portions of the tracks of any street passenger railway company, surface, elevated or underground, or motor power company, as may be required, either to complete a circuit upon any railway constructed, owned or operated under the rights conferred by this act, or to connect any such railway with another railway, upon such terms and conditions as the councils of such cities shall determine: Provided, Compensation for such use shall have been paid or secured.
53 P.S. § 15554