Without vouching for results so favorable to the progress of the work, it is impossible to overlook the importance of the experiment; and the Committee are of opinion that this material, if it can be procured, should be introduced into the tunnel and shafts, and a thorough experiment made, in order to determine whether it can be used with an advantage even approximating to that shown by the first trial.
Experience has proved that the rock at the Hoosac Mountain is of a peculiar character: comparatively easy to drill, but extremely hard to displace, and that its advantageous excavation requires a strong explosive agent. The difference in the use of weak and strong powder is at once observed, and the effect of simultaneous blasting, by the aid of electricity, is proved by the increased progress of the work since it has been used. It would seem evident, then, without the aid of experiment, that an explosive agent, possessing eight times the power of common powder, would be a valuable auxiliary to this undertaking; and that if such an one could be obtained, and safely used, no time should be lost in procuring a supply.
The use of nitro-glycerine in England is not uncommon; its components are well known; and the Committee are informed that it might be advantageously manufactured at any point where it is used.
Electrical Firing.
The experiment of simultaneous blasting by electricity has been made with admitted success. The increased progress in the Central Shaft from an average of about 181/2 to 23 feet per month, demonstrates its utility, and will undoubtedly insure the continuance of that mode of firing in preference to the method formerly practised.
The Troy and Greenfield Railroad.
The completion of the railroad from Greenfield to the tunnel has been contracted for with B. N. Farren, for the sum of $545,000, exclusive of the cost of depot buildings, turn-tables, and engineering expenses. The road to be opened for travel to Shelburne Falls by the 15th of November, 1867, and to the tunnel by the 15th of July, 1868. A lease of the same has been executed to the Fitchburg and the Vermont and Massachusetts Railroad Companies, at a rent of $30,000 per year, to expire on the completion of the tunnel, or whenever the work on the same shall be stopped, by competent authority.
Mr. Farren commenced work under his contract about the 20th of October. At this time there were about four miles of track,—exclusive of that which had to be removed with the trestle-bridges,—built by Mr. Haupt. Some portions of the track were in fair condition; but the larger part of it must be relaid. Many of the ties are of hemlock; they are all decayed and must be removed, and new ones substituted. None of the bridges were strong enough to be used, and the timber of which they were constructed is too much decayed to be used for building purposes: There is on hand in addition to the track laid, chairs, or connecting joints, sufficient to lay five miles of rails; also about ten thousand chestnut ties. Such of these as had been properly piled are sound. Many of them, however, are so much decayed, as to be unfit for use.
The road-bed has in many places been injured by rain and frost. At exposed points near the river, it is entirely destroyed. Comparatively speaking, there was little masonry on the line. With the exception of one pier, the bridge masonry at Green River will be taken down. All the deep ravines were crossed by trestle work, and consequently there were but few culverts. Of these some small ones are still standing in good condition. Of the bank wall built, about one-half remains,—the remainder has either fallen down, or will be taken down and rebuilt.
Very little alteration will be made in the general location of the line or its gradients. The curvature will be very much modified and improved. Some sharp and reversed curves will be entirely saved by the substitution of straight lines. Others, where the expense of reduction is not very heavy, will be materially changed. The alterations below Shelburne Falls are substantially as follows:—