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Our latest exhibition Untangling the Tracks takes a closer look at the Thameslink Programme, a major project to increase capacity, improve connections and provide greater reliability on the Thameslink route. Work started in 2007 and stations were rebuilt, new infrastructure developed, tracks and signalling replaced, and 115 new trains were ordered.

But what is the history behind the only north-south mainline railway to cross London?

The origins of the Thameslink route date back to 1866 with the opening of the London, Chatham & Dover Railway’s (LC&DR) extension over the River Thames. This was despite a Royal Commission ruling in 1846 that railways should terminate at the edge of the city, as it was believed this would help alleviate congestion on the city’s busy streets.

The LC&DR extension travelled north along a viaduct and through the new Snow Hill tunnel to Farringdon, where it could connect with the Metropolitan Railway, and onwards to King’s Cross and St Pancras.

The construction of the extension through the crowded city caused huge disruption, as is clear from an engraving from the time. It is possible to see here how the course of the line changes from viaduct to tunnel.

The Ludgate Hill viaduct was famously depicted by Gustav Doré in London: A Pilgrimage. Ludgate Hill and Fleet Street are shown heaving with people and traffic while a train billows smoke from the viaduct above.

Along the line stations were built at Snow Hill, Holborn Viaduct and Ludgate Hill. Snow Hill station opened in 1874, but passenger services through the tunnel stopped in 1916 (the station had been renamed Holborn Viaduct Low Level in 1912), terminating at Holborn Viaduct station instead. Ludgate Hill station closed in 1929, and only freight services operated through the tunnel until 1969.

In 1986 work began to bring the north-south route through the city back. New Thameslink services started in 1988. Although Thameslink trains follow the same route today as the original LC&DR trains, the viaduct at Ludgate Hill was demolished in 1990 and replaced by a tunnel. Holborn Viaduct station was also closed in 1990, replaced by the nearby City Thameslink station.

The new Thameslink services were busy with commuters, and soon overcrowding on the line had become an issue as passenger numbers in London and the South East increased. The recent Thameslink Programme has revitalised the route, adding greater capacity, and trains now serve destinations from Sussex and Kent to Bedford, Peterborough and Cambridge.

Our Untangling the Tracks exhibition is open until May 2020. Visit to discover how the Thameslink Programme transformed one of the oldest railway networks in the world, through interactive displays and games, mixed media and miniature station models.

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About Laura Sleath

Laura Sleath is a Senior Curator at London Transport Museum, having worked at the Museum since 2012. Laura has taken on both collections management and interpretive roles on various exhibitions including Legacies: London Transport’s Caribbean Workforce, Untangling the Tracks, London Transport at War and Designology.