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The Hidden Secrets of the Royal Mail Underground

The Hidden Secrets of the Royal Mail Underground
© Mike Peel / CC BY-SA 2.0 UK

A hidden underground rail network operated driverless trains to transport the UK’s mail for more than 70 years – yet hardly anyone knew about it! The secret railway service, known as the London Post Office Railway, ran beneath the capital between 1927 and 2003.

It was only in 2017, after the British Postal Museum and Archive opened the route as a circular tour for visitors, that more people became aware of the secret mail service. Also known as the Mail Rail, the fully-electric service ran for 76 years, covering a distance of 6.5 miles.

The route ran from Paddington Sorting Office to Whitechapel Eastern Delivery Office. It had eight stations, each of which coincided with a local sorting office above. The largest station was beneath Mount Pleasant sorting office, on Phoenix Place – the site of the postal museum today.

Railway history

The postal railway was an engineering masterpiece that had taken 16 years to design and build. The underground mail delivery service was the brainchild of Post Office bosses, who were inspired by the Chicago Tunnel Company’s underground freight line in Chicago, Illinois.

They liaised with the Underground Electric Railways Company of London to create a similar line in the capital, with the aim of speeding up mail delivery. The plan was drawn up in 1911 and John Mowlem and Co won the contract to build the tunnels.

Mowlem was one of the UK’s largest construction companies at the time. Founded by John Mowlem in 1822, it was awarded a Royal Warrant in 1902 and was responsible for some major civil engineering projects, such as Billingsgate Fish Market in 1874, Woolwich Ferry terminal in 1889 and Liverpool Street station in 1891.

After the elaborate network of tunnels was designed, building work began in 1915. First, the shafts were dug and then the tunnels were built using the Greathead shield system – a safe method which enabled the miners to work inside a protective metal structure to prevent the collapse of the tunnels.

The deepest tunnels are at a depth of around 70ft and the main line has two tracks in a single 9ft diameter tunnel. Most of the stations are at a shallower depth and the track has a one-in-twenty gradient in places. The route was designed as a narrow gauge, driverless railway.

First delivery

Although work had started during World War One, it was suspended in 1917, as materials were running low due to the war. This caused delays and it was June 1924 before the track-laying started. The first section, between West Central District Office and Paddington, was opened for training in February 1927.

The line officially opened for the Christmas parcel post in December 1927. Letters were first transported in February 1928. The service was expanded between 1954 and 1965, when plans were drawn up for the new Western District Office at Rathbone Place. It was opened by the then Postmaster General, Anthony Wedgwood-Benn.

The elaborate Royal Mail underground rumbled on, largely unnoticed by the public, until 2003. As well as the sorting office and delivery office at either end of the route, there were six further stations corresponding with delivery and sorting offices, including Rathbone Place, Wimpole Street and Bird Street.

Line closure

The Mail Rail carried a staggering four million letters a day for much of the 20th century and kept running throughout the Second World War. On one occasion, during the Blitz, a bomb damaged a tunnel, but it was out of service for only one day, as it was so important to the mail delivery service.

In its heyday, the service operated for 22 hours a day, but in the late 20th century, the stations gradually began to close down. By 2003, only three stations were still in use, as the sorting offices above the others were relocated over the years.

Royal Mail said using the underground railway was five times more expensive than transporting mail by road by that time. The Communication Workers’ Union fought to keep the railway open, arguing it wasn’t as expensive as Royal Mail claimed.

The Greater London Authority compiled a report supporting the railway, saying it was better than having an increase in mail trucks on the already congested roads. It was estimated the railway did the work of 80 trucks per week. However, the underground was closed down and the final mail trains ran on 31st May 2003.

Mobile museum

In April 2011, an organisation called the Consolidation Crew published detailed photographs of the tunnels and reported they were “largely in good condition”. Much of the infrastructure remained in place.

In October 2013, the British Postal Museum and Archive revealed it was to open part of the network to the public as a kind of mobile museum. Islington Council approved the scheme and the £26 million project to create a new museum and railway attraction commenced in 2014.

New tourist trains were installed in 2016, enabling visitors to take a 15-minute trip on a circular route, starting and finishing below Mount Pleasant. On 5th September 2016, the museum and new railway attraction officially opened.

In its first full year of operation, between 2017 and 2018, the trains completed around 9,000 trips, covering a total of 6,213 miles. The railway and museum became major visitor attractions, hosting more than 198,000 visitors. Tourists can see the old station platforms, deep below Mount Pleasant sorting office, while they can also see and hear recordings of the people who worked on the network below-ground.

Former underground engineer Ray Middlesworth recorded some of the narrative, before retiring in 2017. There are interactive exhibits at the museum, bringing to life more than 100 years of postal history.

Future plans

While the museum and underground railway are temporarily closed, due to the COVID-19 pandemic, Royal Mail is operating a virtual tour, so the public can enjoy the experience from their own home.

Royal Mail has no plans to reopen its underground as an operational railway to carry mail. The company ran its own mail trains above-ground until 2004, but after phasing these out, it returned to the general network in 2005. Today, it uses a fully-integrated network of rail, road and air to carry mail.

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