Chunnel
Tunnel

The Channel tunnel between England and France was opened in May 1994. It brings Paris and Brussels within three hours of London. The undersea tunnel was proposed many times since the 1790s, but fear of invasion by the French via the tunnel delayed its construction till almost 200 years later.

The narrowest point between England and France is a stretch of sea some 20 miles wide and known as the English Channel. It is one of the most turbulent sea passages in the world and, for thousands of years, has protected Britain from European invasions, including those planned by Napoleon and Hitler. In the 1790s, a French mining engineer drafted a plan for an undersea tunnel offering a fixed connection between the two countries. In the 1830s, another French engineer dived to the seabed to collect samples for geological observation: These specimens suggested a layer of chalk stretching below the seabed under the channel.

This information was important, as chalk is soft yet impervious to water, making an undersea tunnel practical. In the 1850s, Napoleon III was impressed with detailed plans for a railroad tunnel under the channel. During the 1860s and 70s, British and French engineers and promoters came up with several designs, completed geological surveys, and obtained provisional permission from both governments to construct a Channel tunnel. Work actually began on two pilot tunnels - one from each coast - in 1880, and new boring machines ate up the soft, waterless chalk as if it were a layer of cheese.

Then the trouble started - political, not technical. British military experts warned of the dangers of invasion at night by trainloads of French soldiers. Uncertain politicians halted all work in 1882. Though the scheme was revived several times, the fear of invasion by tunnel continued to prevent its construction. By the 1970s, it was the high cost that stopped further work. Only in the 1980s was there general agreement that the tunnel would be worthwhile, and construction was started in 1988.

The finished tunnel consists of two parallel, single-track rails, or running tunnels, with a service tunnel between them. The length of the route is 50.5 km, of which 37.9 km are under the sea (a distance exceeded only by the tunnel linking the two islands of Japan). The tracks are electrified throughout, so there is no exhaust, meaning there are no ventilation problems. Passengers are carried in sleek expresses unhindered by weather or customs. Automobiles, trucks, and buses are conveyed on special shuttle trains. Much freight is carried through the tunnel.