Rail Engineer has closely followed progress on the London Bridge station rebuilding, track layout enhancements and re-signalling throughout its 4½ year project life. Finally, the work was virtually completed over the Christmas and New Year 2017/18 period, the biggest re-signalling of all the previous stages. The new Thameslink train service will not, however, commence until May 2018 – see separate article.
Much of the Christmas work was concerned with commissioning Platforms 1,2 and 3 at London Bridge, thus allowing Cannon Street trains to once again stop at the station, and to make ready Platforms 4 and 5 for the Thameslink trains.
The final track layout has been brought into use and is now controlled from Three Bridges ROC. Considerable publicity had emerged before Christmas on the intended programme (see RailStaff, December 2017) but, in early January, Rail Engineer went to meet Mark Somers, the project director, in the project control ‘war room’ located at New Cross Gate, to learn how it had all progressed.
London Bridge had been a rail bottle neck from time immemorial, with only two tracks through the notorious Borough Market junction round to Charing Cross, which, with the initial Thameslink service up the spur to Blackfriars, made the already congested railway even worse. No Thameslink trains could operate via London Bridge during the peak hours, and thus something had to be done if Thameslink was going to be the proposed high-frequency cross-city link.
London Bridge station has two sections – the low level terminating platforms and the high level platforms through to Charing Cross and Cannon Street. Rather too many of the former existed (nine) whilst too few of the latter (six) resulted in trains queuing for platform occupancy.
With work commencing in 2013, the first phase was to rebuild and reduce the low level platforms to six so as to create space for additional through lines. This was completed by Christmas 2014, but operating difficulties and staff unfamiliarity caused short-term mayhem at the terminal platforms. Lessons were learned and thereafter the introduction of new facilities became an example for all.
In parallel, a new viaduct was built to permit four tracks round to Charing Cross and Blackfriars, whilst work began to construct the Bermondsey dive-under that would segregate future Thameslink services from Sussex and Kent Coast trains on the approach to London Bridge. By August 2016, the new Charing Cross route Platforms 7, 8 and 9 and their associated approach tracks were opened, and tracks over the new viaduct were commissioned. This enabled the release of the Cannon Street line Platforms 1, 2 and 3 for rebuilding, with train services being maintained over temporary tracks where Platforms 4 and 5 would eventually be.
Christmas 2016 saw the first element of the Bermondsey dive-under brought into use, enabling Croydon and Sussex-bound trains to reach New Cross Gate on a new dedicated line. Modified layout and track changes took place at New Cross and on the London Bridge approaches at the same time.
The penultimate stage, in August 2017, enabled the Cannon Street tracks to revert to their final position. The opening of Platform 6 allowed a full service to Charing Cross to be restored and the re-routing of the Kent lines through the Bermondsey dive under routed Charing Cross services to the south side of the future Thameslink lines. Some additional point work also resulted in better connectivity between the high and low level sides of the station.
In parallel with all the layout and signalling changes, London Bridge station has been totally rebuilt. The once-overall roof on the low level side has long gone, with traditional canopies provided on the new platforms. The upper level concourse is new and a huge street level concourse, giving access to all re-opened platforms, was partially opened. On the high level, new platforms have been constructed. When finished, London Bridge will be a show case station matching, in a very different way, the magnificence of St Pancras, Kings Cross and Liverpool Street.
The Christmas blockade
There was no way, other than by having a 10-day blockade, that the final layout was going to be achieved. The media always chooses to criticise such shut downs, but the alternative terminus of Victoria allowed some trains to be diverted so as to maintain a service. The London Bridge low-level terminal platforms remained operational during most of the blockade period.
The blockade plan was as follows:
- 23 Dec (01:20) to 24 Dec (23:30) – full possession of all lines through London Bridge high level to Charing Cross and Cannon Street, plus lines through Blackfriars;
- 24 Dec (23:30) to 27 Dec (04:00) – all of the above plus the low-level Sussex lines out to Honor Oak Park and Kent lines out to Lewisham, a move which, in any case, coincided with the Christmas rail shut down;
- 27 Dec (04:00) to 30 Dec (01:45) – continuing full possession of London Bridge high-level and lines to Charing Cross and Cannon Street, but with the line from Herne Hill into Blackfriars terminal platforms reopened;
- 30 Dec (01:45) to 1 Jan (08:00) – full possession of all London Bridge high-level lines and all lines into and through Blackfriars;
- 1 Jan (08:00) to 2 Jan (04:00) – all lines reopened but using the period to run test trains over the new layouts to ensure that the full timetabled service could be operated after the Christmas and New Year break.
The actual programme ran more or less to this schedule, with the exception that the signalling testing took longer than expected and was not completed until 16:00 on 1 January. At that point, the possession was given up to allow the conductor rails to be energised whence test trains began running at 19:00. Although this was 11 hours late, the whole programme had a 36-hour contingency built in.
So what was achieved?
Most of the new points and crossings had been laid in before the blockade began so, in theory, it was merely the task of commissioning the new point mechanisms and signals, and placing all of the new signalling under the control of Three Bridges ROC.
It sounds simple, but couple this with the installation of the remaining signal posts, the massive amount of testing to be carried out, the recovery of trackside assets including some signal posts, and the general tidying up of the railway, one begins to understand just how much work is involved and the intricate planning that has to take place beforehand.
The changes to the layout comprised:
- Introducing the new Thameslink lines over the Bermondsey dive under and extending these through Bricklayers Arms towards London Bridge Platforms 4 and 5;
- Continuing the lines from Platforms 4 and 5 northwards and commissioning the new Metropolitan double junction to restore a double-track Snow Hill route up to Blackfriars (the south end of this had been singled under a BR rationalisation plan);
- Restoring the reversible single-track Metropolitan junction to the Cannon Street line, used primarily for empty stock movements (the third side of the Borough Market triangle);
- Converting the line from Blackfriars carriage siding into a third track partway down the Snow Hill route to Metropolitan junction;
- Bringing into use new crossovers between the Kent Fast and Slow lines at North Kent East junction, where the Greenwich line diverges;
- Commissioning lines 3, 4 and 5 southwards from London Bridge towards New Cross. Line 3 will give further flexibility for Cannon Street services and 4 and 5 are in readiness for Thameslink trains to operate into Kent. All these lines, plus lines 1 and 2, were transferred to the control of Three Bridges ROC. Also brought into use was the ‘Southwark reversible spur’ that allows limited access from the Greenwich line to the Charing Cross line platforms and to the low-level terminal platforms.
The new Platforms 1, 2 and 3 at London Bridge opened for Cannon Street services, Platform 2 being reversible to facilitate peak hour flows in the morning and evening.
Although Platforms 4 and 5 are commissioned, they will not be used regularly until Thameslink services commence. However, there are signalled routes through them that will allow Cannon Street and Charing Cross services to access these platforms should congestion occur.
The new track layout and signalling allows considerable flexibility of platform usage to minimise the effects of any signal failures or other disruption.
The extent of the work
The statistics on what has been commissioned gives an idea of the achievement:
- 302 new signals including shunt signals;
- 89 point ends;
- 154 AWS (Automatic Warning System) magnets;
- 324 TPWS (Train Protection and Warning System) track loops;
- 246 track circuits.
Also introduced were around 180 POSA signals (Proceed On Sight Aspect). These are a new feature and consist of two white lights (akin to a shunt signal) that sit beneath or alongside the normal signal red aspect. Should a track circuit fail, which would prevent the aspect clearing to yellow or green, providing the point positions can be proven in the route ahead, the signaller can energise the POSA lights to flash, which allows the driver to proceed on a ‘drive on sight’ basis to the next signal but with the capability of being able to stop if any obstruction is observed.
The POSAs are provided at all controlled signals and some auto signals throughout the London Bridge area. Rather than piecemeal introduction, it was decided to hold off their commissioning until this final stage as driver confusion could result.
New and re-arranged work-stations at Three Bridges ROC were very much part of the job. All remaining routes in the immediate London Bridge area, which were controlled from the old London Bridge power box, have now been transferred to Three Bridges.
The Westlock electronic interlockings have been programmed with new data for the new layouts and revised areas, each of which has required testing to prove that its own functionality is correct, but also to test between the individual interlockings (of which there are 13 in total) to ensure that trains pass seamlessly and safely from one area to the next. An example of this would be the interlockings for the Charing Cross and Cannon Street areas, with considerable train traffic between the two.
Controlling the site As would be expected, a comprehensive briefing document was prepared for all the site works giving details of the various phases, which lines would be under possession and which would be open for traffic, access arrangements including vehicle parking, noise sensitive areas and procedures to ensure safe working practices. Getting staff to read and obey the instructions was a task in itself.
Invaluable has been the provision of on-site CCTV monitoring by strategically placed cameras at various locations throughout the extended London Bridge area, linked back to monitor screens in the control ‘war room’ at New Cross Gate. This facility has been provided by Site-Eye, a company specialising in work site surveillance, which has been used since groundwork commenced.
The contract required one fixed and one pan, tilt and zoom camera at each location and for these to be moved around as work progressed. The cameras use IP technology and are interconnected via the web. Provision has cost around £1 million over the life of the project, but the value has been inestimable. Just visiting the ‘war room’ and seeing the screen bank is enough to convince anyone that having a birds-eye view of everything is invaluable. Instances of people claiming erroneously to have carried out tasks were quickly noticed. Word soon got around!
Despite all this planning and precautions, two safety incidents occurred during the blockade, resulting in minor injuries to two members of staff. One can never be too careful.
Logistics and contractor involvement
A total of 4,500 shifts were worked over the blockade period. In addition to Network Rail personnel, the main contractor, Balfour Beatty, was responsible for track, structures, civil works, electrification and conductor rail provision, with Siemens suppling the signalling and telecom elements. Both had significant numbers of engineers and technicians on duty at London Bridge and Three Bridges.
Such blockades are resource hungry and additional contractor support was provided by Sonic Rail Services for conductor rail bonding, Kent Rail for signalling power supplies, MPI for additional signalling testers, Vital Rail and Pod-Track for civil labour and track teams, and Coyle for extra labour and installation works.
Also needed were NRT (Network Rail Telecom) with its FTN transmission network to provide the resilient links between London Bridge and Three Bridges.
Is that the end?
The morning of 2 January saw the media descend on London Bridge to witness and report on the final stage of rebuilding the station. The street level concourse is now fully open with escalator and stairway access to all platforms, including disabled facilities. It also provides a walkway through from Tooley Street to St Thomas Street and is claimed to be the largest concourse of any station in the UK, which is probably true.
Some retail outlets have still to be taken up and the full ambience is not yet in place. It was inevitable that the station should steal the limelight, but it is the new track and signalling that is the real success story.
In all, 128 different stage works have taken place since 2014, London Bridge probably being the largest single rail project ever undertaken in modern times. It is not, however, the finale, as the prime purpose of introducing 24 trains per hour for the Thameslink central core has still to happen. The requirements and staging of this are detailed in the accompanying article.
The final closure of London Bridge power box will not take place until the Lewisham, Angerstein and Hither Green areas have progressively transferred to Three Bridges over the next two years.
Mark Somers and the project team have mixed feelings now that the works are virtually complete. A well -earned rest is called for, but many may well ask “what shall we do next?” Don’t worry, recent press announcements indicate many more projects in the pipeline.
This article was written by Clive Kessell.