53 Pa. Stat. § 22821
An additional executive department in the government of cities of the second class may be created by ordinance, to be known as the Department of City Transit, which shall be in charge of a City Transit Commission consisting of five (5) residents of the city to be appointed by the mayor, subject to the approval of council, one of whom shall be designated to serve from his appointment until January first, one thousand nine hundred and twenty-six; and one from his appointment until January first, one thousand nine hundred and twenty-seven; one from his appointment until January first, one thousand nine hundred and twenty-eight; one from his appointment until January first, one thousand nine hundred and twenty-nine; and one from his appointment until January first, one thousand nine hundred and thirty. Their respective successors shall be appointed on the expiration of their respective terms to serve five (5) years. An appointment to fill a casual vacancy shall be only for the unexpired portion of the term. Three (3) of the members shall be a quorum. They may make regulations for their own organization and procedure consistent with the laws of this Commonwealth and the ordinances of the city. They shall serve without compensation and shall make annually to the mayor a report of their transactions and recommendations. They may employ a chief engineer and such other persons and employés as may be necessary, whose salaries, together with the necessary expenses of the commission, shall be provided for in the discretion of council by the proper appropriations and ordinances.
53 P.S. § 22821