Engineering Wonders of the World
Volume I

88 ENGINEERING WONDERS OF THE WORLD. nearly 4 miles long—a considerable work in itself. These two measures completely justified themselves. The side heading carried off all the water of the spring into the tunnel, through which it flowed to the Sudbrook pumping-station, and enabled the men to passenger train travelled under the Severn; and within forty-eight hours Mr. Walker left the scene of his arduous and anxious labours for South Africa. But the Great Spring had not said its last word. The great head of imprisoned water produced a pressure of 57| lbs. to the square BRICKING THE TUNNEL. attack the last lengths. On October 17, 1884 —the anniversary of the tidal wave disaster— the headings met, and a way was open from one end of the tunnel to the other. It hap- pened that the chairman of the Great Western Railway paid a surprise visit that day, and so was one of the first to make the passage. On April 18, 1885, at 8 a.m., the last brick of the tunnel was set. Eight weeks afterwards the sluices draining the Great Spring were closed, and water excluded from the tunnel. Three months later the first The Tunnel completed. A Fresh Difficulty to face. inch on the brickwork, which showed serious signs of not being able to stand the strain. Mr. Walker was hurriedly re- called to England to deal with this fresh difficulty. After due consideration, the engineer de- cided to let the Great Spring have its way, and to relieve the brickwork. A special pumping-shaft was sunk at the side of the tunnel, and fitted with six large pumps to deal with the spring water. Two other stations at Sea Wall Shaft and at a shaft situated about five miles from the Gloucestershire en-