When people think of underground London, they usually picture the busy platforms of the Tube. But a whole world lies hidden beneath the modern capital’s streets. From Churchill’s wartime bunker to the Mail Rail.
If you are wondering about what this Mail Rail thing that I just mentioned might be, this article will be perfect for you.
For over 75 years, this dedicated 10-kilometer network of railway sat more than 20 meters below the surface, quietly shuttling millions of letters and parcels between sorting stations across London to keep the city connected.
But long before the Mail Rail arrived in London, postal pioneers explored alternative solutions to the problems that they had at the time. One of these peculiar Victorian innovations was the pneumatic tube. Back in 1863, the London Pneumatic Dispatch Company opened an experimental postal railway beneath Euston Station. This system was clever enough for the time and managed to propel 35 bags of mail more than 500 meters in less than a minute.
While this experiment might look like a success from our perspective now, there were high operating expenses, and it caught up with the company. By 1874, the line closed down permanently after just over a decade of service.
Overcoming Gridlock: The Birth of the Mail Rail
As London grew into a thriving global metropolis, its streets became a traffic nightmare. Horse-drawn carriages took over the roads together with early motor vehicles, and it caused massive gridlocks in some places. This resulted in severe postal delays. As a way to solve this, city planners began designing an automated underground electric railway dedicated entirely to the post. This last sentence sounded futuristic, but that was done in 1909!
Construction kicked off in 1914, but the timing was exceptionally unfortunate since the outbreak of the First World War halted the project. After things got back to normal, the necessary electrical operating equipment was put together, and the Mail Rail opened its doors on December 1927. Arriving just in time to help handle the chaotic Christmas rush!
How the Underground Postal System Worked
By now you might be wondering how the Mail Rail and the underground postal system worked. This innovative postal network stretched from Paddington in West London to Liverpool Street and the Eastern District office. It was designed as a marvel of efficiency and helped the post move between regional postal centers.
Once loaded onto driverless electric trains, the mail traveled through a single 80 cm wide tunnel that branched out as it approached individual stations. These compact trains looked like something out of an amusement park ride! But they were heavy-duty.
At its operational peak, in a time before e-mails, the Mail Rail ran for 22 hours a day and moved four million letters every day, slashing cross-London transit times from hours to a mere 30 minutes.
Riding the Mail Rail Today at the Postal Museum
As digital communication evolved and operational expenses climbed, the legendary postal service ceased operations in May 2003. And, for years, the silent postal tunnels under London were only seen by urban explorers. Luckily, with the launch of The British Postal Museum & Archive in 2004, things started changing. By 2017, there was an expansion, and the museum changed its name to The Postal Museum. There, they reopened a stretch of track in London’s Mail Rail.
As I mentioned before, the compact trains looked like something out of an amusement park, and if that sounded interesting to you, you will love to learn that you can ride those trains today. This was the reason I went to the Postal Museum in April 2026.
Even though the Postal Museum is quite fascinating, the main experience there is the subterranean ride in a modified passenger-friendly train that runs through the original tracks under the Mount Pleasant sorting office, once one of the largest postal sorting facilities in the world.
I’m not a small person, so sitting in the train carriages felt like I was back in my childhood. The carriages are small, a little less than one meter wide, and have a curved transparent plastic top that sits just above your head. Based on the fact that I was the only adult there without kids, this feels more like a kid’s adventure than anything else. But I can easily say that I loved every minute of it.
As you travel through the small tunnels past historic sandbags and stalactites, you are guided by the recorded commentary of Ray Middlesworth; he will share the story behind the Mail Rail. He worked as an engineer and spent over three decades working in the Mail Rail while it was still active. After that, he carefully maintained the tunnels after closure, and his voice brings the old platforms back to life!
The ride feels like a charming ghost train ride, and you will pass by a small train graveyard where old carriages rest in the dark tunnels. And there is even a brief but dramatic experience where you will see how the Second World War blackouts felt when the power failed deep under London. Based on my face in the pictures here, I loved every minute of this trip on the Mail Rail.
Exploring London’s Forgotten Subterranean Railway
The postal experience continues across two modern buildings packed with history. And I think you can browse the highlights in 45 minutes or spend a full afternoon diving into the exhibits.
The exhibits tells a fascinating story on the evolution of communication. The postal system was originally founded by King Henry VIII as a strictly private courier service for the monarchy. And I learned that every English town was required to keep three fresh horses ready at all times to sprint royal news across the kingdom. It wasn’t until the 17th century, under King Charles I, that the network opened to the public.
Since my main focus on the Postal Museum was the Rail Mail, I browsed through the highlights, but I could see myself exploring the exhibits with more patience. And I’m pretty sure I will do this soon since I want to ride the Mail Rail again.
When you leave the museum, it is impossible not to feel a wave of nostalgia for the beautiful, fading art of handwritten letters. And the unexpected futurism of an electric driverless train under the city. If you are looking for a unique London adventure, swap the standard tourist sights for the unforgettable rumble of the Mail Rail.
Inside The Postal Museum and the Mail Rail: London’s Best Hidden Subterranean Adventure
15-20 Phoenix Place
London—WC1X 0DA
