Section 11B. Notwithstanding the provisions of chapter one hundred and sixty-one A to the contrary, any city or town may, for the purpose of providing public transportation facilities or avoiding a reduction or discontinuance of such transportation facilities or for the purpose of the securing of grants from appropriate federal agencies, enter into agreements to contribute to the costs of such services with any person lawfully authorized to operate any motor bus on any public way therein for the carrying of passengers for hire. The contribution to the costs of services shall include the purchase, sale or leasing of transportation equipment by said city or town.