Bermondsey dive-under

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51°29′55″N 0°04′33″W / 51.4986°N 0.0757°W / 51.4986; -0.0757

100m
110yds

Bermondsey dive-under

  

The Bermondsey dive-under is a significant piece of rail infrastructure to the south of

History

Railway lines in south London wound over the docks and each other on

The first example of a flying junction in the United Kingdom was the Weaver Junction that opened on 13 November 1881. Here the grade separation was used to raise one track over the oncoming mainline on a double junction.^[4]

In 2000, commuter services south of Thames were using the legacy tracks of a century earlier.

Construction history

Construction of the dive-under was complicated as existing services had to be maintained through the construction. Work commenced during 2013, with bridge-strengthening works near London Bridge station completed in June 2013.^[5] The first track was used for services from 27 December 2016, two new lines for SouthEastern traffic came into service after the August bank holiday. The overall programme of work was scheduled to be completed in January 2018. ^{[6] [7]}

• 2011 the Borough Market viaduct was completed, doubling the available tracks to the west of London Bridge station, it was commissioned in January 2016.^[8]
• Demolish Bricklayers Arms branch viaduct and rebuild to new profile in preparation for future use.
• Restricted timetable imposed
• Southeastern lines 3 & 4 were taken out of use and realigned. These were temporarily resignalled as lines 5 & 6, and used while lines 5 & 6 were taken out.
• Dive downs constructed. Side walls constructed. Piling.
• The dive-under box was built. This took a year to complete.
• Trackbed for the terminating Brighton slow downline laid and tested, and is operational on 27 December 2016 giving 3 line running capacity.
• Later, in August 2017, the Charing Cross tracks were diverted to their new permanent route using the dive-under, freeing the rest of the Southeastern part of the site for the installation of the final layout during 2018. At the same time work preparation was made for the new Thameslink dedicated tracks, ready to open the new through route via London Bridge.
• In January 2018 the new Thameslink London Bridge route opens. In December 2018, the timetable made its annual change. There are an additional 16 (tph) trains per hour through to Farringdon and St Pancras (previously 1 tph), 24tph in all including the new Luton to Rainham service.^[9]

Description

v t e Mainline railways around the South Bank
Legend
South West Main Line to Weymouth Hungerford Bridge over River Thames Waterloo Charing Cross Waterloo East ( 1864– 1868 ) Blackfriars Elephant & Castle Blackfriars Holborn Viaduct–Herne Hill line to Herne Hill (and e.g. to Sutton) Snow Hill tunnel/City Widened Lines to St Pancras (and to MML & ECML) ( 1864– 1885 ) Blackfriars Bridge City Thameslink Brighton Main Line to Brighton London Bridge Cannon Street South Eastern Main Line to SE London and Kent River Thames

London Bridge is the fourth busiest station in the United Kingdom, serving around 54–56 million passengers a year.^[10]

Previously, northbound Thameslink trains arrived into London Bridge to the south of the Kent lines. Thameslink trains needed to use the pair of tracks to the north, and Charing Cross trains needed to use the new pair of tracks to the south. The Brighton Main Line terminates here.

In simplest terms, the existing Charing Cross tracks dive under two tracks now reallocated to the new dedicated Thameslink service. Most tracks seen from above remain in roughly the same location as before though scheme there is a slight realignment to allow the two critical Thameslink and Charing Cross services routes to switch over from one side to the other. The changes to the vertical height of the tracks are significant. There are tight constraints both vertically and horizontally.^[9]

The modification was undertaken to the east of London Bridge so that Thameslink trains from the Brighton Main Line can use a grade-separated crossover to avoid impeding trains from Kent bound for Charing Cross.^[11][12] The Charing Cross services on the Kent lines are diverted slightly south in the vicinity of Trundleys Road onto the route of the former