That the board of directors of any drainage district organized under chapter 215 of the Laws of 1905, and acts amendatory thereof and supplemental thereto, and located in counties having a population of 140,000 inhabitants or over, shall have power, independent of and distinct from the powers heretofore given, to contract with any railroad company to revet, maintain and keep in repair the whole or any part of the banks, and to construct, maintain and keep in repair the whole or any part of any levees such board has heretofore, or by its order may hereafter, declare it necessary to revet, maintain, construct or keep in repair adjacent to the tracks or right of way of such railroad in such district, upon such terms as the board of directors shall determine to be for the best interests of such district; and for such purpose such board shall have the further power to levy general taxes, not exceeding the limit now prescribed by law for the general fund, and appropriate from such general fund, on hand at the time of the passage of this act, or sums that may hereafter be raised by such levy, and pay to such company for such construction work, repairs and maintenance, in one sum, or in not exceeding five annual installments, such reasonable proportion of the total cost thereof as said board shall determine in such contract; not, however, in an amount in excess of the sum of $60,000: Provided, That not more than one contract shall be made for such work, and to grant to such railroad company the right of way for the construction, maintenance and operation of a railroad, over, on, along or across such levees and landward thereof.