The Stanedge Tunnel on the Huddersfield Branch of the London and North-Western Railway is exactly 3 miles long, and it is also a single line tunnel; the gradient is nearly a level. The time for passenger trains through it is six minutes, or at the rate of 30 miles an hour; the time for goods trains is nine minutes, or at the rate of 20 miles an hour. The deepest portion of the tunnel is 600 feet below the upper surface of the mountain. On the 3rd September, 1867, we came through the Shepherd’s Well Tunnel of the London, Chatham and Dover Railway, 2,376 yards long, against the gradient, which is 1 in 100, or 53 feet in the mile for two-thirds of its length, and the remainder nearly level, in two minutes fifteen seconds; on the same day we came through the tunnel in the opposite direction, when the time occupied was one minute forty-two seconds: on the other hand, Mr. Allport, the General Manager of the Midland Railway, to whom we gladly acknowledge ourselves indebted for much valuable information most obligingly afforded, says that the passenger trains are timed to run _in each direction_ through the Dove’s Hole Tunnel 2,420 feet long at the same rate of speed, and actually do run at that speed—nearly 46 miles an hour,—yet the gradient is 1 in 90, or 58⅔ feet per mile. The same for goods trains, their speed is 23 miles an hour in each direction, and Mr. Allport assures us they maintain it in both directions. The following are the lengths of some of the principal railway tunnels in Great Britain and of the two longest in Ireland:— Name. Company. Yards.