Section 3 contains the following provisions: "The governor and council shall annually appoint a state engineer for the purpose of examining and determining monthly the amount and value of the work done, and materials delivered on the railroad and tunnel of the Troy and Greenfield Railroad Company, who shall receive an annual salary of one thousand dollars, payable quarterly. The state engineer shall forthwith fix permanent marks in each end of the Hoosac Tunnel, marking the progress of the work up to February twenty-fourth, eighteen hundred and sixty, from which to determine the progress subsequently made. He shall also determine by suitable notes, marks or observations, the amount and value of all grading, bridging, masonry, or other work done, or iron, or other materials delivered on the road east of the Hoosac Tunnel, prior to December twenty-second, eighteen hundred and fifty-nine, and fix data from which to determine the value of any work, or materials delivered subsequent to the date last named. He shall monthly, immediately after the first day of each month, estimate the proportion which' the work done upon the road, since the preceding estimate, bears to the whole of the work required to be done in the graduation, masonry, bridging, and superstructure of said railroad east of the Hoosac Tunnel; and also the work done in the excavation of said tunnel, which he shall certify separately to the governor, together with the amount of state scrip to which the company is entitled under the provisions of this Act. Such monthly estimates shall be based upon a width of road-bed at grade of fifteen feet, on embankments, seventeen and a half feet in side cuts, and twenty feet in through cuts; in the heading of the tunnel upon dimensions fourteen feet wide and six feet high in the middle, and in the finished excavation of the tunnel of fourteen feet wide and eighteen feet high in the middle. "The deliveries of scrip shall be at the rate of fifty dollars for each lineal foot of tunnel, divided between heading and full-sized tunnel, in the proportion of thirty dollars for each lineal foot of heading and twenty dollars per lineal foot for the remaining excavation; and of six hundred and fifty thousand dollars for the whole of the graduation, masonry, bridging, and superstructure of the unfinished portion of the road east of the tunnel. "The Scrip shall be delivered on the road in the proportion which the value of the work done and the materials delivered each month bears to the estimated cost of the whole work and materials required on the portion of road aforesaid. "No expenditures shall be required merely for the purposes of ornament, but the work shall be substantially performed, and the rails shall weigh not less than fifty-six pounds to the lineal yard; for any defective materials or work, a proportionate amount of scrip shall be withheld.