Gasworks Tunnel

The first of the tunnel bores was built as part of the construction of the Great Northern Railway between 1851 and 1852,^[3] and was intended to carry the railway below the Regent's Canal.^[8] The original tunnel now forms the central of three parallel bores. A second bore to the east was built in 1878, and a third one to the west in 1892. The Gasworks Tunnel's construction was particularly challenging due to the steep gradient and narrow clearances of the railway.^[3] The tunnel was named after the Gas Light and Coke Company, which had a gasworks to the south of Regents Canal near the railway.^[9]

On 29 December 1893, a passenger train travelling from King's Cross to Hatfield collided with seven empty coaches that were being shunted into the station to be used in an express service. In his report to the Board of Trade on the accident, railway engineer Horatio Arthur Yorke concluded that it was caused by an unexplained derailment of goods coaches, but that it was exacerbated by poor arrangements for shunting through the tunnels, which he called "hardly satisfactory".^[10]

v t e Copenhagen and Gasworks Tunnels
Legend
to Finsbury Park Fast lines Slow lines Copenhagen Tunnel Copenhagen Junction to North London line to High Speed 1 to Canal Tunnels via Canal Tunnel Junction Regent's Canal Gasworks Tunnel to London King's Cross

On 10 December 1900, an express train travelling from Leeds to King's Cross became stuck in the Gasworks Tunnel due to rail slip, which then delayed other trains. The train managed to restart itself without external intervention.^[11] During World War II, some express services ran by the London and North Eastern Railway were so long that they stretched into the tunnel when the locomotive stopped at the buffers at King's Cross, including trains of more than twenty cars.^[12] On 4 February 1945, the King's Cross railway accident occurred when a heavy train of 17 coaches weighing approximately 590 long tons (600 t; 660 short tons) hauled by a Class A4 locomotive was unable to achieve the climb through the Gasworks Tunnel, slipped to a standstill and rolled back into the station, killing two passengers and injuring 25 others.^[13]

British Rail carried out electrification of the southern part of the East Coast Main Line with 25 kV AC overhead lines from London King's Cross to Hitchin between 1976 and 1977. This was authorised in 1971 for the benefit of London suburban services as part of the Great Northern Suburban Electrification Project.^[14] In 1977, the Gasworks Tunnel's eastern bore was taken out of use and its track bed removed.^[15][16] The closure formed part of the remodelling and rationalisation of the station, and other works included a completely new layout between the bores and the platforms, the introduction of bi-directional working in all three bores,^[16][17] and works to improve headroom at the southern end of the tunnel.^[16]

As part of its modernisation program, British Rail also began segregating trains by concentrating the suburban services in the western bore and long-distance services in the central bore.^[16] At the time of the eastern bore's closure, it had only ever been used by steam trains, and this had caused significant soot build-up in the Gasworks Tunnel which had to be removed during its renovation and reinstatement.^[18]

As part of a larger modernisation program of London King's Cross and the East Coast Main Line, the eastern bore of the Gasworks Tunnel was reopened.^[15] Works began in August 2019 when 11,000 tonnes of spoil were removed from the bore before a new track bed was installed.^[2][19] The reopened bore meant that the number of tracks before the station throat increased from four to six, and this allowed for a 50% increase in capacity at King's Cross.^[2]

Because the Gasworks Tunnel sits below residential property, the track bed was built with elastic mats that soaked up vibrations.^[15] The works were made more difficult by the presence of third-party construction including piling above the bore, as well as the age and conditions inside. The inside of the bore was noisy and dusty with low visibility and mobile phone signal, which all presented extra challenges to contractors.^[19]

During a six-day closure of platforms 0–6 at King's Cross railway station on 25–30 December 2020, the station throat at King's Cross was redesigned to incorporate the reopening of the eastern bore.^[2][17] Overhead line equipment was added to the eastern bore during this closure, as well as new signalling and waterproofing for the Gasworks Tunnel. Platform zero was rebuilt to align with the bore, with services originally planned to start on 7 June 2021.^[2] The first London North Eastern Railway (LNER) train passed through the eastern bore at 07:01 on 26 April 2021, before arriving into the newly built platform zero.^[20]

In January 2024, the Gasworks Tunnel and the neighbouring Copenhagen Tunnel became the first in the country to have new signal-boosting technology fitted inside. This stops devices from losing signal and allows passengers to continue calls while travelling through the Gasworks Tunnel. The upgrade was funded entirely by the LNER.^[21] As of May 2025^[update], the operators travelling into King's Cross via the Gasworks Tunnel include Grand Central,^[22] Great Northern and Thameslink,^[23] Hull Trains,^[24] London North Eastern Railway,^[25] and Lumo.^[26]

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