An Act amending the act of June 27, 1939 (P. L. 1207, No. 405), entitled, as amended, "An act regulating the appointment, promotion, suspension, reduction, removal, and reinstatement of employes (except chiefs and chief clerks) in bureaus of fire and fire alarm operators and fire box inspectors in bureaus of electricity, in cities of the second class;....," further providing for engine and truck companies housed together and eliminating units.