Tunneling The Simplon

Little has been heard lately of the project for tunneling the Simplón, bul lt would appear at last to have taksn final shape, if the Allgemelne Zeitung is to be trusted. says the Manchester Guardian. The tunnel when completed wlll be the fourth to pierce the Alpine barrler, but it differs considerably from either the Mont Cents, the St. Gothard, or the Arïberg tunnels because lts great length of 'about twelve and one-third miles, half as much again as the length of the Mont Cenis tunnel and nearly twlce the length of the Arlberg tunnel, has made the work of construction peculiarly difflcult. To secure proper ventilation wlll be far from easy and the engineers will have further to devise a mear.s for lowering the tempera ture, which, it is estimated, wlll be iO4 degrees Fahrenhelt, for the tunnel will be very deep, 2,372 yards of superincumbent earth rising vertically from it in one place to the summit of the mountain. lts course may be roughly described as the chord of an are made by the famous Simplón road, which was constructed by Frenen engineers between 1801 and 1806. The northern opening is near Brieg, the southern near Iselle. The distlnctlve feature of the project is that two parallel tunnels are to be constructed about 220 yards apart and connected at intervals by galleries running diagonally from one to the other. Each tunnel is eighteen and one-third feet high and íifteen feet broad at the level of the floor and will contain one line of rails. Both tunnels will be constructed simultaneously, but at flrst only one is used for trame, the other being reserved and utilized for purposes of ventilation. Meanwhüe the existence of two conneoting tunnels will greatly facilítate the task of exeavating either of them. Rubbish wlll be more quickly removed, machinery will be more easily brought to the rock face, and if any falls of the roof occur it wlll be poseible to rescue the workmen and repair the damage. The work is to be pushed on from both sides at onoe. The galleries have for the first few yards to be excavated by hand, and it is estimatd that the progress then made will ' only at the rate of a meter a day.