TUNNELS AMONG THE ANCIENTS.—HOW THEY WERE MADE.—MODERN TUNNELS AND THEIR LENGTH.—LAUGHABLE INCIDENTS IN RAILWAY TUNNELS.—THE TWO LOVERS.—THE ANXIOUS FRENCHMAN.—ROBBERS.—THE HOOSAC TUNNEL.—ITS HISTORY.—THE AUTHOR’S VISIT.—NATURE AND PROGRESS OF THE WORK.—AN EXPLOSION.—ACCIDENT FROM NITRO-GLYCERINE.—THE CENTRAL SHAFT.—THE TERRIBLE CALAMITY OF 1867.
Quite recently I picked up a newspaper about thirty years old, and read in it an account of the great engineering difficulties which had been overcome in the construction of the Boston and Lowell Railway.
This road, twenty-five miles in length, was among the earliest constructed in America, there being less than half a dozen railway lines which are older. The account proceeded to say that the great obstacle was the deep cut through solid rock, near the city of Lowell; and I can remember, in my boyhood days, riding over this road, and as we reached the cut, the attention of passengers was called to it, and at least half our number projected their heads through the windows to look at the wonderful work. Three times was the work let out on contract, and twice did the contractors fail, one of them failing not only to complete the work, but to pay the men he employed. The third contractor succeeded, but I believe he made no money out of his speculation.
This once famous cut through solid rock is only a few hundred feet in length, and I think about forty feet in depth. It has dwarfed into almost microscopic insignificance by hundreds of other railway cuts in this country and in Europe.
Railway tunnels were at that day unknown, though tunnels existed in Europe for other purposes, some of them of very ancient date.
LENGTH AND EXTENT OF TUNNELS.
Tunnelling, in civil engineering, is an underground passage usually constructed for conducting a canal or road beneath elevated ground. In mining the term is also sometimes applied to horizontal excavations. Tunnels are more common in Europe upon railways and canals than in this country. In the United States the total length of tunnels is not more than one mile for every thousand miles of road. In Great Britain it is considered cheaper to tunnel through rocks than to make open cuts deeper than sixty feet. In England the Wood-head Tunnel exceeds three miles in length; and there is another on the London and North-western Railway nearly three miles long. Twelve or fifteen others on different roads exceed one mile each. The Box Tunnel on the Great Western Railway, between Bath and Chippenham, is thirty-one hundred and twenty-three yards long, or rather more than one and three fourth miles.
On the canals of England there are five tunnels exceeding three thousand yards in length. The longest of these is the Marsden Tunnel, fifty-five hundred yards long. In France there is one tunnel on the St. Quentin Canal over thirteen thousand yards long.
Some of the tunnels of the ancient Romans were quite extensive in their character. One which was constructed by the Emperor Claudius was cleared out some years since by the Italian government. It proved to be about three miles long, thirty feet high, and twenty-eight feet wide at the entrance, and was nowhere less than twenty feet high.