Discussion. Summit-Level Tunnel of the Bettws and Festiniog Railway.

Abstract

desired to make a few remarks with regard M~.Eckersley.to the cost of the tunnel, which appeared to him to be excessive. He had had considerable experience in rock tunnels, and he knew that many had been executed at a cost of from 7s. to 22s. per cubic yard. When the Paper by Mr. Sopwith on the Mont Cenis Tunnel was read before the Institution' in 1864, Nr. Eckersley made some observations on the subject ; and he was considered to have taken a rather exaggerated view of the cost, which he estimated a t 5240 per lineal yard. In a second Paper on the same subject2 by Mr. Sopmith, it was stated that the cost was S206 per yard. Allowing for the cost of the lining and for the necessary works in connection with the boring apparatus, it might be fairly stated that the rock excavation had cost 2160 per lineal yard, which, a t 80 cubic yards to the lineal yard, would amount to about 40s. per cubic yard. From communications made to the Institution by Illr. D. E. Clark, respecting the St. Gothard t~n n e l ,~ he gathered that the cost of the rock excavation was about 359. or 36s. per cubic yard. He had examined the specimens of the rock taken from the Bettws tunnel, as exhibited by the Author, and he could see no reason why the cost of the excavation should be 48s. per yard. The work, he believed, was carried out by the London and North Western Railway Company ; but however desirous engineers might be to do their duty, it was impossible for an agent, placed as Mr. Smith would be, to carry out work of that kind as economically as a contractor could do it. He could not help thinking that if the tunnel had been placed in the hands of a contractor, who would, in his own interest, na!urally look most carefully after every detail, the cost of this work would have been fully one-third less. H e had himself executed a tunnel in Hungary where the rock was much harder than any of the specimens exhibited. It was driven from two faces; it was not so long as the Festiniog tunnel, and there were no shafts, but the cost was only 26s. per cubic yard. Taking the cost of the shafts and the lining of the tunnel at the south end a t 520,000, which was a large estimate, the cost would still be %70 per lineal yard, or about 45s. per cubic yard. question why the tunnel had cost so much, which he ventured to Colonel BEAUNONT said there was a tolerably simple answer to the Col. Beaumont.