The Chunnel is an informal nickname for the Channel Tunnel, a 31-mile (50.5 km) railway tunnel that runs beneath the English Channel, connecting England to France. It links Folkestone in Kent, UK, to Coquelles near Calais in northern France, passing under the Strait of Dover. With 23.5 miles of its length running beneath the sea, it holds the record for the longest undersea tunnel in the world.
What the Tunnel Actually Looks Like Inside
The Channel Tunnel isn’t a single tube. It consists of three parallel tunnels bored through the rock beneath the seabed. Two of these are full-size rail tunnels that carry train traffic in opposite directions. Between them runs a smaller service tunnel used for maintenance, ventilation, and emergency evacuation.
The tunnels sit, on average, about 148 feet below the seabed and reach a maximum depth of 75 meters (246 feet) below sea level. Cross-passages connect the service tunnel to the two main tunnels at regular intervals, roughly every 325 to 375 meters. In an emergency, passengers can evacuate through these passages into the service tunnel, which has its own ventilation system capable of pushing smoke in either direction to keep escape routes clear.
How Engineers Built It
Construction relied on 11 massive tunnel boring machines, each roughly the size of two football fields. Teams drilled from both sides of the Channel simultaneously, starting from the English coast and the French coast, and it took about three years for the machines to meet in the middle. On an average day, crews advanced around 250 feet.
The key to the project was geology. Beneath the seabed, engineers identified four distinct layers of sediment: grey chalk, chalk marl, glauconitic marl, and gault clay. They chose to bore through the chalk marl layer, which sat 80 to 100 feet thick. This rock was ideal because it’s impermeable to groundwater, soft enough to excavate efficiently, and strong enough to support itself without requiring concrete walls along much of the route. By tunneling about 50 feet below the grey chalk layer above, they also avoided fractures that could cause swelling and water seepage.
The English boring machines were driven deep into the seabed and simply buried in place when their work was done. The French machines completed their sections and were dismantled.
Two Ways to Cross
Two distinct services use the tunnel, and they’re often confused. Eurostar is a high-speed passenger train. You board at London St Pancras (or stations in Brussels, Paris, and Lille), sit in a regular train seat, and pass through the tunnel in about 20 minutes as part of a longer journey. You can’t bring a car.
LeShuttle (formerly Eurotunnel Le Shuttle) is an entirely different service. You drive your vehicle onto a specially designed train at the Folkestone terminal, stay with your car for the 35-minute crossing, and drive off at the Calais terminal. LeShuttle carries cars, motorbikes, campervans, caravans, coaches, and freight lorries, with up to seven departures per hour. You cannot travel as a foot passenger on LeShuttle; you need to be in or on a vehicle.
How Many People Use It
In a typical year before the pandemic, the tunnel moved millions of passengers and enormous volumes of freight. Even in 2020, a year heavily disrupted by travel restrictions, about 8.3 million passengers traveled through the tunnel on Eurostar and LeShuttle combined, alongside roughly 1.45 million freight vehicles on LeShuttle and over a million tonnes of goods on dedicated freight trains. In normal years, those numbers are significantly higher.
The tunnel is operated by Getlink, a Franco-British company that has managed the infrastructure for over 30 years. Getlink oversees both the physical tunnel and the LeShuttle vehicle service, while Eurostar operates independently as a separate train company using the same tracks.
Why “Chunnel”?
The nickname blends “Channel” and “tunnel” into a single word. It caught on in casual conversation and news coverage during the construction boom of the late 1980s and early 1990s. The formal name remains the Channel Tunnel (or in French, Tunnel sous la Manche), and the operating companies use that in all official contexts. But for most English speakers searching online or chatting about a trip to France, it’s simply the Chunnel.