It shall be lawful for, and the right is hereby conferred upon, cities of the second class of this Commonwealth, to purchase, lease, locate, construct, and equip, or otherwise acquire, transit facilities, or any one or more of them; and to own, maintain, use, and operate the same within their respective corporate limits, and within the limits of adjacent cities, boroughs, and townships: Provided, Such right shall only be exercised, by any of said cities, within the limits of adjacent cities, boroughs, and townships, subject to the consent and approval of the proper authorities of such adjacent cities, boroughs, and townships, lawfully empowered to regulate or to consent to the construction, maintenance, and operation of such transit facilities therein.