Underwater Railways

The wonderful world of trains has a fascinating history, but the more recent advancements might be even more interesting. While everyone news about the Underground Railway in London, there are now underwater railways operating in several parts of the world.

The first ever underwater railway tunnel was a test run in Kibblesworth in 1855. This was 23 meters under the surface of the rivers and ran around 396 meters long. The main idea behind such tunnels was and still is to reduce the time taken by railway travels. When a railway tunnel is underwater, it doesn’t have most of the obstacles that the railway tracks on land have to navigate. With faster speeds, trains operating below river or sea level may also be better for the environment as they consume less fuel.

An empty railway track

While underwater railways are still not common, they do exist and are in operation. Whether someone loves riding in trains or just like movies that have a train in them, the idea of an underwater train ride is thrilling. However, most of the underwater railways today only have a section that’s actually below the water surface. Let’s get into more details with some examples of underwater trains and railways today:

1. The Thames Tunnel 

The Thames Tunnel

The Thames Tunnel was constructed in 1843, and is an important part of the history of trains. It’s among the oldest underwater tunnels in existence, and was made with tunneling shield technology. The main aim here was to connect Wrapping and Rotherhithe, two historic cities. Now, the Thames Tunnel is among the most famous London train routes as well as a major tourist attraction.

This tunnel stretches just 400 meters long, which is less than a quarter of a mile. It’s 20 feet high, 35 feet wide, and around 75 feet deep when the river is at high tide. This is also the first known tunnel to be successfully constructed inside a navigable river.

While the original purpose of the Thames Tunnel was to transport horse-drawn carriages, pedestrians would use it most of the time. Since it was underwater, this was a unique experience that attracted many tourists as well. Finally, the tunnel was converted for railway use in 1869 as part of the East London Line. From 2010 onwards, this line falls under the London Overground network.

2. Gotthard Base Tunnel


This is an underwater tunnel that lies under the surface of the sea, with a depth of around 1.4 miles. The route here is between Milan and Zurich, among the Swiss Alps.

In this tunnel, trains can cover over 35 miles in 20 minutes. Almost 2,000 miles of copper cables have been used to construct this long tunnel.

The Gotthard Base Tunnel began its operations on the 1st of June in 2016, with full services starting in December of that same year. It’s currently among the deepest traffic tunnels and longest railways in the world. It’s also the first low-level, flat route through the Swiss Alps and the third tunnel that connects the Ticio and Uri cantons.

This tunnel lies within the New Railway Link through the Alps project and is usually called a base tunnel. Its main aim was to increase the capacity of local transport along the Alpine barrier. More specifically, this tunnel would reduce the chances of fatal crashes by shifting freight volumes from land trucks to trains. In addition to making things safer, the GBT is also better for the environment and makes transport quicker by almost an hour.

3. The Channel Tunnel

The Channel Tunnel

This train tunnel connects England to the rest of Europe through the English Channel. It’s an inter-country tunnel that has an undersea span of almost 24 miles. It was first proposed at the start of the 1800s, along with the idea of building a tiny artificial island in the center of the channel to make maintenance easier. The initial purpose was for transportation by a road, but now the network also has a fast train.

The length of this 250-feet deep tunnel makes it the longest underwater part of any known tunnel on the globe. It’s also the third-longest railway tunnel. At present, it carries some high-speed Eurostar trains, which are mostly for passengers. There have been many updates and upgrades to the tunnel over the years, keeping in mind the necessity for ventilation, cooling, and drainage.

4. Seikan Tunnel


This railway tunnel is located in Japan, and was the longest, deepest railway tunnel in the world at the time of its construction in 1988. It spans a little above 14 miles and is about 459 feet deep. It’s an undersea tunnel, with a train route that connects Hokkaido Island with Aomori Prefecture.

The name of this tunnel is derived from the Japanese characters of the nearest major cities on each end. In the beginning, there was only 3 feet and 6 inches of narrow-gauge track inside the tunnel. In 2005, though, the Hokkaido Shinkansen project began laying a dual gauge track. There are also some proposed extensions which are meant to be finished by the year 2031.

There are also two stations inside the tunnel, mostly for the purpose of being emergency escape points should the need arise. With these stations, the tunnel gets the safety status of a much shorter passage. There are also exhaust fans for extracting smoke in case of a fire, TV cameras for helping to guide passengers, and fire alarm systems in place along with nozzles for spraying water. Incidentally, these are the two first underwater railway stations in the world.

5. Marmaray


This underground railway tunnel started out as a dream that the Turkish Sultan Abdul Majeed had about 150 years ago. While another sultan also proposed an underwater crossing, the plan was not to come into being just yet.

The construction of the Marmaray Tunnel started in 2004 and was intended to connect eastern and western Istanbul. It’s located in the Bosphorous strait and was around 623 feet deep at the time.

There are two single-track tunnels in the large main tunnel. Three underground railway stations are also situated along the way; their names are Üsküdar, Yenikapı, and Sirkeci.

The Marmaray Tunnel was opened to the public and passengers in October 2013. In early 2019, the overground area of the project was also completed, making it possible for normal train and traffic movements to proceed. At present, this tunnel is believed to be the world’s deepest immersed tube tunnel.

By late 2017, the Marmaray tunnels had more than 300 scheduled trains every day. Their deepest point is 200 feet below the surface of the sea.

Further Plans for Underwater Railways

Further Plans for Underwater Railways

The underwater railways we’ve discussed above have been fairly successful so far. Of course, their construction and engineering does take a long time and is not always the safest kind of work. However, there’s still a long way to go when it comes to underwater travel; especially if we want to go for even longer routes.

Many people may love the fun heritage railways in America, but some may also wonder what happened to the plans for an underwater railway from China to America. Given the political issues and the relationship between the two countries at the moment, such a huge collaboration is unlikely at present. Plus, the sheer length of the railway will require a lot of financial investment, personal risk, and high chances of accidents.

There have also been plans to connect the Indian city Mumbai to the UAE. This would mean an underground railway spanning almost 1243 miles. If the project comes to fruition, it will be the longest underwater railway in the world.

How Safe are Underwater Railways

How Safe are Underwater Railways

Underwater trains or at least underwater travel has been considered since the 1800s. The technology for burning these goals, however, requires a constant sort of development to make sure that everything remains safe and speedy. There is always risk when it comes to transportation, whether on land or water. Still, there’s much more risk when you’re traveling underwater and have to rely on tunnels to keep you safe.

Before constructing any tunnel for railway transportation, engineers and planners have to consider every conceivable issue that may arise. Fires can break out, seals can pop, and natural disasters may occur to wipe out several thousand people at once.

At present, traveling underwater by train is also a luxury and tourist attraction. Those who can afford it and like the thrill can pay for rides in the luxury trains as well.


Underwater railways can provide quicker and more eco-friendly travel than land or air vehicles as long as they use high-speed trains. With larger projects being undertaken and more people wanting to commute quickly, we might soon see many more miles of underground railways in the future.