Royal Mail has announced that it has signed a sponsorship agreement for Mail Rail at The Postal Museum, supported by Royal Mail, an exhibition and ride due to open in July 2017.

The five-year partnership will see Royal Mail and The Postal Museum work together to give visitors a chance to experience the network first-hand for the first time in its 100-year history, revealing its surprising stories and experiencing what it was like to transport mail underground. For the first time, trains carrying people, rather than post, will ride a looping mile of track around Mount Pleasant station.

Moya Greene, Royal Mail's Chief Executive Officer, said: "We are delighted to be supporting Mail Rail at The Postal Museum, an exciting new exhibit and ride. Over the last 500 years, the delivery of mail has changed beyond recognition, from a small group of King's Messengers to a national network connecting people, companies and communities across the UK. During this time Royal Mail has been responsible for a number of world firsts.

"Transporting mail underground is definitely one of them. We are excited for people to experience this forgotten gem in mail delivery".

Royal Mail first conceived the concept of transporting mail underground in the mid-1800s. The pneumatic system, which ran from Euston station to Eversholt Street sorting office, launched in 1863 and saw rail cars sucked or blown through a tunnel.

The idea was revisited in the early twentieth century, when congested streets and pollution meant that mail, which was being transported by road between main Post Offices and railway stations in London, was severely delayed. Excavation and building work began on creating an underground rail network - seventy feet below ground - in 1913. A year later, work on the rail was put on pause during the First World War.

The rail, which ran from Paddington District Sorting Office in the west to the Eastern District Sorting Office at Whitechapel, finally opened in late 1927 and used electrically powered driverless trains.

Ninety narrow gauge trains originally ran over the twenty-two miles of track in the system, which was operational for more than seventy-six years. At its peak the railway was running twenty-two hours a day, moving millions of items of mail across the capital. In a single day, it could carry up to four million letters and parcels.

Dr Adrian Steel, Director at The Postal Museum, said: "Mail Rail was an unprecedented engineering marvel in its time, and is testament to the innovation and dedication of Royal Mail throughout its 500 years to ever speed up communication.

"Royal Mail is a very fitting sponsor and we look forward to working together to bring this amazing piece of history to life and making Mail Rail at The Postal Museum a major, successful attraction".

The Postal Museum is set to open in July at Phoenix Place, London, WC1X.