Mail Rail: London’s Secret Underground Post Railway You Can Actually Ride

Millions of people ride the Tube every week. Very few know that for most of the 20th century there was another railway under London, running beneath their feet, with no passengers and no drivers. Its only job was to move the post.

It was called the Post Office (London) Railway, or Mail Rail, and it’s one of the best rare finds in the capital, because unlike most “secret London” stories, you can actually go and ride part of it.

A railway built for letters

By the early 1900s, London’s streets were jammed, and moving mail between the big sorting offices and mainline stations by road was slow. The answer was to go underground.

According to the Postal Museum, the plan was for six and a half miles of tunnels at an average of 70 feet below ground, linking the West and East ends of London, with eight stations including Paddington, Mount Pleasant and Liverpool Street (>The Postal Museum: The story of Mail Rail).

Tunnelling began in 1914 (some sources, like the National Transport Trust, say 1915) and was finished by 1917. But the First World War got in the way: the Treasury wouldn’t let the Post Office order the operating equipment during wartime, and high material prices after the war meant work didn’t restart until 1923 (>The Postal Museum).

Opening day, 1927

The railway finally opened on 5 December 1927, carrying parcels between Mount Pleasant and Paddington. Letters followed on 13 February 1928 (>The Postal Museum).

What makes it remarkable is how advanced it was. The trains were electric and driverless from the start (>National Transport Trust), decades before driverless trains became something people talked about. They ran on a 2ft gauge track, in a single tunnel just 9ft across, splitting into two 7ft tunnels at the stations (>The Postal Museum).

The stations were built to look like miniature Tube stations, with curved walls and that familiar rumble of an approaching train. The only difference was who was waiting on the platform: postal workers loading sacks, not commuters.

22 hours a day, through the Blitz

Mail Rail was a workhorse. The Postal Museum says it kept the post “coursing through London for 22 hours every day” (>The Postal Museum: Mail Rail). The National Transport Trust says it ran continuously for 76 years, including through the Blitz (>National Transport Trust).

It even had its own underground workshop beneath Mount Pleasant, where engineers kept the system running (>The Postal Museum).

Why it closed

In the end, the world changed around it. As sorting offices above ground closed and mail moved in different ways, the railway became uneconomic. In 2003 the system was suspended, and it remains closed as a working postal line (>The Postal Museum).

For years, the tunnels just sat there in the dark, with the trains and stations largely left as they were.

Back from the dark: the ride

Then came the twist. With National Lottery funding, the Postal Museum turned part of the old network into a visitor ride. The museum opened on 28 July 2017 and Mail Rail opened to the public on 4 September 2017 (>The Postal Museum: Our history), bringing the tunnels back to life as a ride for the first time in their 100-year history (>National Lottery Heritage Fund).

Here’s what the museum says the ride involves (>The Postal Museum: Mail Rail):

• You go down into the old engineering depot and board a miniature train into the original tunnels.
• You descend to 21 metres (70 feet) underground, through tunnels just 2.1 metres (7 feet) wide at their narrowest.
• You see the unchanged station platforms deep below Royal Mail’s Mount Pleasant sorting office, with audio-visual shows about the railway’s 1930s heyday.
• The ride takes about 15 minutes including boarding, with a top speed of 7.5mph.
• There’s pitch darkness, loud noises and some flashing lights, so it’s worth knowing if anyone in your group is sensitive to those.

The trains themselves are new, based on Mail Rail designs used from 1987 but with a lowered floor so passengers can sit, because the tunnels are only about seven feet high (>National Transport Trust). Tall people: mind your head, metaphorically at least.

Why it’s a proper rare find

Plenty of “hidden London” stories are about places you’ll never get into: sealed Tube stations, deep shelters, government bunkers. Mail Rail is different. It’s a genuine piece of engineering history, driverless and electric from day one, hidden in plain sight for most of a century, and it’s open to the public.

It also says something about Britain that we rather love. Faced with gridlocked streets, someone in the Post Office decided the sensible answer was to dig a private railway 70 feet under London just for letters. And then it worked, every day, for 76 years.

How to visit

Mail Rail is part of the Postal Museum in Farringdon, central London, across the road from the main galleries (>The Postal Museum: Mail Rail). The museum’s site lists opening as Tuesday to Sunday, 10:00 to 17:00, with the last Mail Rail ride at 16:00 (>The Postal Museum: Mail Rail). Times and prices change, so check the official site and book ahead before you go.

There’s step-free access to the entrance, and a lift down to the ride level (>The Postal Museum: Mail Rail).

Told straight: if you’re in London and fancy something you won’t find on every tourist list, this is it. A tiny train, a dark tunnel and a story most Londoners have never heard.