Over the Christmas and New Year period, Network Rail delivered a number of projects between London and Cumbria. These included a major railway junction renewal in Buckinghamshire, signalling system upgrades at Preston station, platform improvements at Milton Keynes and Wolverton stations, a bridge strengthening project in Stafford, and the demolition and rebuilding of a 130-metre-long railway bridge over the M6 at Clifton near Penrith.
However, one project delivered during this period didn’t receive much popular media coverage, despite being a £61 million project to modernise 1960s signalling systems, which were the oldest electrical signalling on the West Coast Mail Line. This took place at Kingmoor just north of Carlisle.
The work began in April 2025, and has been delivered by Siemens Mobility as the principal contractor, assisted by a number of companies including L.B. Foster and Haigh Rail. The project included providing new lightweight LED signal heads and structures; track circuit train detection systems to monitor train movements, upgrades to track and points (including the replacement of air powered points); overhaul of signalling power supplies; renewal and changes to the existing control panels for signallers in Carlisle signal box; and upgrading the CCTV system at Floriston level crossing.
On Wednesday 7 January, all systems went live after a seven-day closure of the line between Carlisle and Lockerbie for final installation, testing and commissioning.
Interlockings
The area was last resignalled over 60 years ago in 1963. Two relay ‘free wired’ interlockings were then provided at Kingmoor and Etterby, controlled from a new power signal box at Kingmoor. The relays in the interlockings were known as pre-BR960 relays. Air-powered Electro-Pneumatic (EP) points were provided, along with low voltage DC track circuits and colour light signals. This installation replaced mechanical signal boxes located at Etterby Junction, Kingmoor Junction, Moss Band Junction, and Rockcliffe.
In the 1970s, major resignalling took place on the London Midland Region of British Rail north of Weaver Junction in Cheshire to the Scottish border, with the provision of continuous multiple aspect colour light signalling worked from three new Power Signal Boxes (PSB) at Warrington, Preston, and Carlisle. Unlike Kingmoor, all the interlockings were Westinghouse Westpac Mark IIIa geographical sets, fitted with plug in relays and connected using plug couplers. The geographical units were pre-wired and tested in the factory and housed in lineside relay rooms linked to the signal boxes via TDM remote control systems. All the points were motorised type 63 machines.
Carlisle PSB replaced 46 mechanical signal boxes in 1973, but as the Kingmoor and Etterby interlockings and associated signalling were only 10 years old they were simply recontrolled to Carlisle PSB. A new Westpac Mark IIIa geographical interlocking was provided at Gretna Junction to the north of Kingmoor and Etterby, marking the northern limit of the London Midland Region. Kingmoor PSB was abandoned in January 1973 and it can still be seen to the west if travelling north of Carlisle towards Scotland. Over the years the Warrington, Preston, and Carlisle PSBs have been upgraded, including new Westpac Mark IIIa relay bases in all interlockings, but the older Kingmoor and Etterby areas mainly stayed as they were, including the EP points.
The area has been considered for signalling renewal a number of times. For example it was assessed in the early days of Railtrack 30 years ago, but it was determined that the signalling on the southern part of the LM Region was in greater need of renewal. It is a credit to the providers of the 1963 Kingmoor installation and the maintainers over the years that the electrical relay-based signalling (and the EP points) remained in operation for over 60 years.
Signalling Infrastructure Condition Assessments (SICA) is the process used by Network Rail to evaluate the condition of its signalling assets and to determine when assets need to be renewed. A set of questions are used to assess the physical condition, environment, reliability, and maintainability of an asset, with samples taken from multiple assets within an interlocking area. A condition score is determined for each asset type which is used to estimate when the asset will need an intervention to life extend the signalling or if it should be renewed.
Primary surveys are less detailed and are performed earlier in the asset’s life. Secondary SICA surveys are more detailed and are performed on assets that are approaching the end of their life. So, in the case of Kingmoor and Etterby, secondary SICA checks monitored the signalling condition and eventually confirmed that it did need including in the renewals work bank.
New Siemens signalling
To replace the relay interlockings, an electronic computer-based Westlock interlocking has been provided in a cubicle in Carlisle PSB. Siemens has also provided Kingmoor Interlocking Management System (IMS), which communicates between the new Kingmoor Westlock and trackside signalling via a new Westronic system. This also manages the signallers panel inputs and outputs for the Kingmoor area, and interfaces with Floriston Level Crossing, providing controls and indications for the level crossing on the panel.
The new panel faceplate at Carlisle PSB, supplied by L.B. Foster, features a new Westcad SPAD Monitor which enables Signals Passed at Danger (SPAD) to be detected and monitored on the panel for the first time. This is known as Predetermined Overrun Protection (POP) Signal Group Replacement Control (SGRC).
Carlisle Train Describer (TD) was also modified as part of the project, with its connection to Network Rail’s SMART train information system being removed and reconnected to Kingmoor IMS. With this change Kingmoor IMS now passes all available S Class messages, for the Kingmoor area, over to SMART system for the first time. S Class messages are capable of reporting the status of a number of signalling elements, such as whether a signal is displaying its most restrictive aspect, whether points are set normal or reverse, the status of a Train Ready To Start (TRTS) button, used by train dispatch staff to indicate to the signaller that a departure is due, and whether level crossings barriers are lowered or raised.
Dorman LED signal heads have been provided on new folding structures and the DC track circuits replaced to remove the low voltage track circuits. The air powered points EP points have been replaced with clamp lock points, and the communications from Carlisle PSB to line side object controllers is via dedicated fibre with diversity provided via FTNx. Floriston level crossing CCTV has also been upgraded and uses the FTNx network.
The project was essentially a like-for-like signalling renewal in modern form, but other benefits to make the area more operationally flexible included removing the conditional double reds and providing more effective overlaps.
Conditional double reds are a signalling control to manage train movements at junctions. They hold a signal at red until a train has passed a specific TPWS Over Speed System (OSS) at the point of conflict, known as the Safe Overrun Distance (SOD). Another operational benefit has been a change to the signalling of the Kingmoor Up Avoiding Line. Previously, control of this section had to handed over and back to the depot from Carlisle PSB, but now the Carlisle signaller is in complete control of this section.
There is one more stage of the project to complete with the renewal of the Westpac Mark IIIa geographical interlocking at Gretna Junction, with commissioning planned in 2027.
Matt Kent, director of operations and manufacturing, rail infrastructure at Siemens Mobility UK&I, summed up the project when he said: “We are proud to have partnered with Network Rail to successfully deliver the Kingmoor resignalling project, a key milestone in our mission to transform rail travel and transport on the West Coast Main Line.
“This extensive signalling upgrade includes state-of-the-art digital trackside equipment, fully compatible with Siemens European Train Control System (ETCS) equipment to enable future integration. These enhancements will help future-proof the line, delivering enhanced reliability and efficiency for both passengers and freight.”
The author is most grateful to the Network Rail project team for its assistance with this article.