SECT. 11. Said board of trustees is hereby authorized and directed to lease in perpetuity, or for such term of years as the governor and council may approve, the franchises and property, and thereafter to maintain, improve and operate the railroad, with its branches, of the Fitchburg Railroad Company, on the terms following: twenty-five per cent. of the gross earnings of said leased railroad and property shall be reserved annually by said board of trustees as a specific fund, out of which they shall pay to said company a yearly rental equal to ten per cent. on the present capital stock of said company, free of all taxes upon the stockholders or said company, and also on an additional capital stock of one hundred thousand dollars, which said company is hereby authorized to issue and hold for its own benefit, or such a proportion of said rental, not exceeding said ten per cent. and said taxes, as said reserved fund shall be sufficient to pay: _provided_, _however_, that in no year shall there be paid to said company a rental of less than eight per cent. on said capital stock and said taxes; and to the payment of such minimum rental, said board of trustees is authorized to pledge the faith of the Commonwealth. The surplus of said reserved fund shall be annually passed to the account of earnings. When said lease shall have been executed, and while the same continues in force, said Fitchburg Railroad Company may elect, from time to time, for a term not exceeding five years, one trustee, who shall be added to said board of trustees, and, upon being sworn to the faithful performance of his duties, shall become an incorporated member of the State Board of Trustees of the Hoosac Tunnel Railroad; and said company may fill vacancies for the remainder of the term. SECT. 12. Said board of trustees is hereby authorized and directed to lease the franchises and property, and thereafter to maintain, improve and operate the railroad, with its branches, of the Troy and Boston Railroad Company, and shall pay therefor an annual rental equal to twenty-five per cent. of the gross earnings of said leased railroad and property. When said lease shall have been executed, and while the same continues in force, said Troy and Boston Railroad Company may elect, from time to time, for a term not exceeding five years, one trustee, who shall be added to said board of trustees, and upon being sworn to the faithful performance of his duties, shall become an incorporated member of the State Board of Trustees of the Hoosac Tunnel Railroad; and said company may fill vacancies for the remainder of the term.