East Coast Mainline Routes & Branches Part 1: Thameslink Works


Back in February we published an in-depth look at the past and future of Finsbury Park Station. We noted that the future of Finsbury Park is being shaped by two projects designed to improve capacity and connectivity on the East Coast Mainline. One of these projects is the segregation of suburban services on the Hertford Loop, and this will be explored in detail in Part 2. Here, we will look at the work being undertaken on the ECML to integrate it into Thameslink.

The St. Pancras Canal Tunnels Link

In a somewhat uncharacteristic piece of forward planning, tunnels were dug under the Regents Canal to link the Thameslink core to the ECML during the engineering works to link High Speed 1 (HS1) to St. Pancras Station. The St. Pancras International extension included a new Thameslink station (opened 2007) to replace King’s Cross Thameslink, and the new tunnel was connected to Thameslink here, with a dive-under junction on the northbound line. However the link was not fitted out with track, and the junction was lifted to prevent wear-and-tear during the many years in which the junction and tunnel would not be in use.

Canal Tunnels worksite on York Way

The Canal Tunnels worksite on York Way

Canal Tunnels worksite 2

The worksite

Since the start of 2013 work has been under way to fit-out the link. There are two reasons why this is being done some five years in advance of passenger services using the tunnel. First, the new Thameslink Class 700 rolling stock is due to begin arriving in 2015, and is expected to be used on both the existing Thameslink and Great Northern routes. As we will see below, one of the Thameslink depots will be at Hornsey on the ECML. Therefore the Class 700s may utilise the link for stock movements some three years in advance of passenger services.

The second factor determining an early start to works is that there is currently an expanse of undeveloped land next to the ECML-end portal, known as the ‘Islington Triangle Site’. This is the only part of the Kings Cross Railway Lands development to lie in the borough of Islington rather than Camden. Network Rail have taken advantage of this space to facilitate their works on opening the tunnel portal and are preparing for the installation of the Belle Isle flat junction later this year. Given how Argent’s development of the Railway Lands has accelerated in the last two years this seems a prudent move.

It is exceptionally difficult to find a vantage-point from which to capture images of the works on the ECML-end portal. Therefore please accept our apologies for these grainy pictures, which unfortunately had to be snapped through the ever-filthy windows of a First Capital Connect Class 313.

StP tunnel 1

The St. Pancras Tunnel

StP tunnel 2

Another view of the Tunnel

StP tunnel 3

Our apologies for quality

Hornsey Depot

Further up the line, work on the Thameslink Hornsey Depot and related track-tweaking is now well-advanced. This is a key part of the Thameslink infrastructure, required to service the expected 12 and 8-car Class 700 stock. Network Rail had quite a battle to get the depot approved as Haringey Council fought hard against the original design, which was nearly twice as tall. The new design was approved at the end of 2011. Already the frame is in place, and cladding was making rapid progress when these photos were taken last month. This is also a difficult site to photograph up-close, unfortunately, and some creative clambering was required to capture images. On the other hand the depot is a striking new addition to the view from Alexandra Palace, from where the full scale of the structure can be appreciated.

Hornsey Depot pano from Ally Pally

Wide view of Hornsey Depot from Alexandra Palace

Hornsey Depot from AllyPally

A closer view of Hornsey Depot

Hornsey Depot Closeup

Hornsey Depot on the ground

Platform Extensions

At Finsbury Park Station, the 12-car extension of platforms 3 and 5 has already been completed. These platforms will cater for Thameslink fast services through to Cambridge. However, there is still some doubt as to the service patterns of the future 8-car Thameslink services which are due to largely supplant the current Welwyn inner-suburban service to Moorgate (which may continue to have two trains an hour to supplement the segregated Hertford Loop service). Most affected stations, including Alexandra Palace and Finsbury Park, can already cater for 8-car trains. However, the long-neglected Harringay and Hornsey stations can only handle 6-cars, and their extension may not be easy.

Platform works at FP

Platform extension work at Finsbury Park

Further, following the completion of suburban line segregation, unless money is found to build new platform faces, Hertford Loop services will no longer be able to call at those two stations, leaving them reliant on Welwyn services (whether those heading to/from Moorgate or through the Thameslink core) to maintain current service levels; we will explore this further in Part 2. After local pressure, the DfT confirmed that Thameslink 8-car trains will stop at Harringay & Hornsey, but as yet there is no word on whether platforms will be extended or whether these stations will rely on the politically-problematic Selective Door Opening. As we have highlighted before here on London Reconnections, Thameslink’s final shape remains partially opaque even with only three years left to completion.

Key Dates

  • 2014: Thameslink/ECML tunnel link fit-out complete

  • 2015 (early): Hornsey Thameslink depot complete.

  • 2015: New Siemens Thameslink Class 700 trains due to begin delivery. Due to run on both the Thameslink and Great Northern routes from 2015.
  • 2018: ECML services begin to run through the Thameslink core
Written by Arkady