Christmas 2017 saw major resignalling work in the West Midlands, along with the replacement of a key junction near Smethwick. The work included new signalling equipment and headway improvements introduced on routes between Birmingham and Wolverhampton (via Sandwell & Dudley and via Aston), together with the majority of signalling control moved from Birmingham New Street PSB to the West Midlands Signalling Centre (WMSC).
The £246 million scheme is part of the overall £600 million programme to upgrade signalling across the West Midlands, which includes Bromsgrove, Wolverhampton, Walsall and Coventry as well as on the route between Stourbridge and Banbury via Birmingham Snow Hill.
Rail Engineer has previously reported on the extensive West Midlands resignalling plan in issues 133 and 147 (November 2015 and January 2017), with the 1960s power signalboxes (PSB) control areas being transferring to the WMSC. The first was Coventry (1962-2007), followed by Bescot (1965-2013), Walsall (1965-2013), Wolverhampton (1965-2015) and Saltley (1969 – 2016). This only left Birmingham New Street PSB, from 1966, still operational, although the route towards Bromsgrove was transferred to the WMSC in November 2016.
Covering New Street North and New Street East, Phases 4 and 5 of the programme were safely and successfully commissioned by Siemens following an 11-day blockade between 23 December and 3 January, representing the culmination of a programme of work which began in October 2015.
Once phase 6 is completed in May 2018, with the signalling between Birmingham New Street and Birmingham International stations also replaced and recontrolled, only one signalling position, that controlling New Street station itself, will remain at Birmingham New Street PSB. It is likely to be another four years before the station area itself is resignalled and recontrolled to the WMSC, as the signalling in the area is large and complex. So, this article is about Birmingham New Street PSB resignalling, but minus Birmingham New Street itself!
Birmingham New Street Power Signal Box is a Grade II listed building designed in 1964 by architects Bicknell and Hamilton in collaboration with R L Moorcraft, the British Rail regional architect for the London Midland Region. The building is very much a ‘one off’, constructed on a very difficult and congested site, and is a dramatic building of subjective architectural quality and with a strong sculptural form.
It consists of horizontal pre-cast concrete cladding units of a bold triangular profile, hung from a reinforced concrete frame. The building has a flat roof, typical of the time, and stands five storeys high above railway track level and four storeys above street level. The signalling entry-exit ‘NX panel’ control room on the top level is surrounded by a projecting flat roof to provide shading for the panel. The area of control stretched from Hampton-in-Arden in the east to Tipton in the west and embraced parts of the New Street-avoiding ‘Grand Junction’ lines and the Cross City route.
The Westpac Mark One geographical interlockings and supporting entry-exit NX panels used in the Birmingham area have lasted well, given that they have been used intensively for over 52 years, but the asset condition was starting to provide cause for concern.
Some 30 years ago, the interlocking at Soho Junction was affected by a fire, and it is thought that the foam to contain the fire may have contributed to the wire degradation that has been identified and managed. Elsewhere, track circuit failures have been caused by core failures in trackside cables, and wiring terminations were starting the fail. Part-renewal of some of the elements, such as the train-describer and telephone-concentrator systems, had already taken place, but complete resignalling was considered the only option. This would also allow improvements to headway and layout to be implemented, and provide a firm, stable platform for other network enhancements, such as new stations that are planned for the area.
The Westpac Mark 1 interlockings at Perry Bar, Dudley Port, Soho Junction and Galton Junction have all been recovered to provide additional strategic spares to keep New Street PSB going for a few more years.
Siemens’ project team installed a new Trackguard Westlock interlocking and Controlguide Westcad control system at the WMSC.
Remodelling at Soho North junction
This opportunity to remodel and rationalise, and to improve reliability and flexibility, has taken place at a number of locations. This included intense activity of track renewal and remodelling at Soho North junction, the major junction between Birmingham and Wolverhampton. A temporary speed restriction, due to deficient track geometry, was removed and the turnout speed to the curve increased from 10 to 15mph. This may not seem much of an improvement, but this has decreased the time it takes a freight train to transverse the junction by 50 per cent. The work was successfully delivered, ahead of programme, by the Colas Rail/AECOM/Network Rail S&C South Alliance.
Galton Junction has been remodelled, and a set of switch diamonds has also been removed and replaced with a crossover and a turnout to provide better operational flexibility in times of perturbation. Additional turn back facilities have also been provided at Galton Bridge and Smethwick Rolfe Street to better manage train services in and out of Birmingham when things go wrong. Similar improvements have also been made at Aston.
On the line towards Wolverhampton via Sandwell & Dudley, the signal spacing has been improved to provide a three-minute headway along with additional signalling sections on a very busy stretch of railway. When similar improvements were made as a result of Wolverhampton resignalling, there was positive feedback from drivers on the improved drivability of the route, and the signalling asset manager is hopeful of receiving similar favourable feedback for this phase.
Thales AZLM axle counters have been provided for train detection throughout the scheme, along with VMS LED signal heads with voltage proving. Traditionally, filament signals were ‘proven’ as being operational with the signal lamp filament connected in series with a lamp-proving relay. Should the lamp fail, current would not be drawn through the relay causing it to ‘drop’ and instigate action to be taken along with protecting the route.
LED aspect signals, being more efficient, may not draw sufficient current to operate the proving relay and require special circuitry in the signal head to operate the relay by drawing more current than is actually required by the signal. Voltage proving uses a voltage-free contact in the LED signal head to indicate the status of the aspect to the control system, thus saving current and energy. The savings may be small, but it all helps and is a step in the right direction in providing a sustainable and greener railway system. Voltage proving also removes another potential failure point in the system.
While voltage proving has previously been used in modular signalling schemes, it is believed that Birmingham New Street is one of the first large traditional resignalling schemes to use this type of aspect proving.
A challenge at New Street was to provide what will be the remaining signalling position at the PSB with adequate look-back and visibility of approaching trains due to the complexity of the station, with 13 platforms to the north and 12 to the south. The ergonomic study of the complex operating requirements resulted in retaining more of the NX panel than was originally planned, and the provision of a 32-inch overview screen connected to the WMSC system to provide track indications of approaching trains. Communications between the remote workstation and remaining panel has also been subject to a lot of work and evaluation to minimise the risk of separation.
Data connections from the interlockings to trackside functional modules are essential for schemes of this type, and the Network Rail Fixed Telecoms Network with IP connections via Cisco and Keymile routers and switches have been used. Voice communications at the WMSC were provided by earlier phases of the resignalling programme, with built-in capacity ready for the New Street phases.
The telecoms requirements for the New Street signalling were also designed, installed and commissioned Siemens. Voice services at WMSC are based on a centralised Cisco Unified Communications Manager (CUCM), acting as a voice concentrator with its functionality spread across distributed nodes.
The opportunity has also been taken to migrate some of the legacy voice services off the obsolete Nokia pulse code modulation systems in the area and allowing their recovery.
Stakeholder management is important in all schemes of this nature, and regular constructive engagement meetings have been taking place since February 2017, with the scheme one of the top-five Network Rail Christmas 2017 projects. The stakeholder meetings included representatives from all the affected train operators as well as organisations such as British Transport Police and Birmingham City Council.
The work was planned to take place between 21:30 on Saturday 23 December 2017 and 04:00 on Wednesday 3 January 2018. Four-hour conferences took place to monitor and report progress over this period. The work was compromised by high winds and poor weather conditions, particularly on Christmas Eve and Boxing Day, but it did not impact the programme too much, with the majority of stages outperforming their programme.
The signalling for Phase 5 was signed into use on 27 December, allowing trains into the New Street station area from the Wolverhampton direction via the Grand Junction line. Phase 4 was then available for the enterprise information system (EIS) on 3 January 2018.
Over the commissioning period, Siemens had in excess of 200 testers, along with 100 installation and civils staff, working in shifts around-the-clock to complete the works. This included erecting new signals and installing four-foot equipment – once the track works had been completed by the S&C South Alliance track team.
As well as the scope, scale and complexity of the work, which covered 43 track miles, the inclement weather with heavy snow and ice hamperd the work to install signal bases within the first two shifts. Five solid-state interlocking data fringes also had to be changed over, by the morning of 25 December.
On the 28th, an overhead fault at Duddeston caused pantograph arcing, but work to rectify the problem did not impact on the programme. On the 29th, wheels free testing was underway with 350 of the 446 test logs already closed.
On 2 January, it was confirmed that 26 of the 30 milestones were complete and all routes were signed into service early at 02:37 on 3 January.
A good quality of installation has been provided and this, along with good cooperation and trust established with the maintainer, is enabling a smooth handover to the maintainer. A member of the maintenance organisation was embedded into the project from an early stage and plans are in place to complete the handover from the project to the maintainer within a few weeks, rather than several months, as has been the case with such schemes in the past.
Euston route in May
The new Proof House junction workstation has already been commissioned and is operational in the WMSC. However, it will not be brought fully into use until May 2018, as part of Phase 6 which will include the New Street to Euston route between Proof House junction and Birmingham International following the recontrol of Proof House interlocking and the resignalling of Stechford.
Headway improvements similar to the north of Birmingham will also be provided between New Street and Birmingham International. This will complete the three-minute headway in the corridor between Wolverhampton and Euston. Turnback signals will be provided at Birmingham International, making all platforms fully reversible, along with improvements in the Proof House junction area by re-designed the overlaps and routing tables.
While the complete closure of New Street PSB is four years away, planning and development is already underway for another complex phase. This includes managing the non-compliant overlaps in the station area and the development and approval of a serial interface from the Westlock system to the axle counters. This will reduce the amount of trackside equipment, which is essential for the cramped station area, and provide better reliability with fewer interfaces.
The new arrangement will include a ‘2:3’ fault-tolerant control system with three processors so that, if any two agree, the third is disregarded and the signalling system continues to work. This is a marked improvement over a conventional 2:2 processor control system, in which there are two processors and both have to agree before giving an instruction to a signal to display green aspect – there is no failure tolerance as both processors have to work.
Thanks to Graham Wire, Martyn Naylor and Richard Dugdale of Network Rail for their assistance with this article.
This article was written by Paul Darlington.