Much has been reported on the progress of the European Train Control System (ETCS) on the East Coast Main Line. Though this is not the first main line deployment, it will be the first with lineside signals removed. Many of you will know that, back in the mid-1990s, the Great Western Main Line (GWML) was originally equipped with a trial Automatic Train Protection (ATP) system, known then as BR-ATP but latterly called GW-ATP.
This was before ETCS was to become the European standard and it gave the then British Rail an opportunity to evaluate both the benefits and likely cost of introducing ATP to the national network. A limited number of main routes on the GWML were duly equipped and many, but not all, trains were fitted with the on-board kit. Included within the programme was the branch to Heathrow airport which opened in 1998 and was extended to Terminal 5 in 2008, plus the associated trains.
Although, for various reasons, the system failed to prevent the accidents at Southall and Ladbroke Grove, it operated successfully but was recognised as old technology which would be difficult to keep operational in the longer term. Another emerging factor was Crossrail, (now the Elizabeth Line), where the trains would be running to Heathrow and ultimately to Reading. More recently, new trains (the Class 387) were introduced on to the Paddington Heathrow service and it was deemed undesirable to fit the trains with GW-ATP.
As such, the decision was made not to proceed with GW-ATP as a future BR standard ATP system but instead to move forward with ETCS which was then being developed within Europe. Recognising that this would delay the introduction of an ATP system for several years, an agreement was reached to develop the Train Protection and Warning System (TPWS) as an upgrade to AWS to give an improved train protection facility in the interim period. TPWS has proved to be remarkably successful, which is fortuitous as ETCS has taken much longer than envisaged to reach maturity.
It was hoped that TPWS would be agreed for use on the Heathrow branch but high-level decision making ruled that the branch must not become less safe than the protection GW-ATP provided. TPWS was therefore not approved which meant that ETCS would need to be fitted to the branch and extended back towards London. The technology and software at this time was being deployed in various European countries but was not completely developed as an accepted technology in the UK.
However, a contract was placed with Alstom to equip the route with ETCS as an overlay to the existing signalling system. The ongoing project has been a significant challenge, not because the technology was deficient but because the levels of testing and satisfying the various safety and approval bodies became a project in itself. A talk given recently to the London & South East section of the IRSE gave chapter and verse of all that took place.
Project scope
Introducing ETCS has so far embraced two stages: Stage A covered the Heathrow tunnels and branch back to Airport Junction and Stage B extended the coverage eastwards from Airport Junction to Ealing Broadway. ETCS would be borne on the GSM-R radio link meaning that 100% coverage would be required on both the surface railway and in tunnels. Both the Class 387s and the Elizabeth Line Class 345 trains would need to be fitted to serve Heathrow airport. The Class 345s were already being fitted with the Siemens Trainguard CBTC system for the central London section but would now be fitted with ETCS as well as TPWS and AWS, with some difficult transitions between the various systems.
Project planning
The project was thus faced with having to provide the ETCS technology on both the Heathrow branch and superimposed on to a mixed traffic railway from Airport Junction eastwards towards Paddington already equipped with GW-ATP, TPWS, and AWS. Only when the design was assured could installation and operational testing begin on site. Establishing the detailed parameters for the project was indicative of things to come. An early problem was the constant changes of staff inside Network Rail.
In the end, it required 253 items within the project to be scrutinised and transferred from Alstom into the project portfolio. This involved weekly online meetings with people from the UK, Belgium, France, Netherlands, and Cyprus participating, these locations representing the design offices involved as well as the customer organisations.
With participants from Network Rail, the Network Rail Independent Safety Assessor (ISA), the Network Rail Assessment Body (AsBo), the Network Rail Approval Body (ApBo), the Alstom ISA, and the Alstom ApBo, one gets a picture as to the procedures that emerged. Each of these required an expert to review the various recommendations. Included was a requirement to list the hazard and safety requirements. It took 35 meetings to sort out the project hazard log. The AsBo people attended these meetings as an observer. The risk assessments included:
- Speed restriction process.
- Transition failures when moving from ETCS to conventional signalling.
- Heathrow branch entry controls.
- Balise groupings.
- Out of area staff responsibilities.
- Test logs.
A Safety Integration Forum was established with a monthly meeting to co-ordinate the activities of Network Rail, the relevant TOCs including the Elizabeth Line, Heathrow Airport Express, and the AsBo. Rolling stock issues emerged for the different classes of train – the Class 345s and 387s – plus any rolling stock in regular use on the Western and Wales route that was being fitted with ETCS as part of the nationwide fitment programme. These latter could well use ETCS on the Stage B section, which would now have ETCS, GW-ATP, TPWS, and AWS. It is no wonder that, with so many variables and challenges, it took far longer and cost a lot more than originally envisaged.
Project design and initial testing
Once the design was underway, it required extensive modelling and laboratory testing by Alstom principally at its Charleroi premises in Belgium. Included in this was the installed ETCS equipment on the Bombardier manufactured Class 345s which had been built at Derby. Bombardier train building interests have since been acquired by Alstom but other than placing the contract under a single company, this was of little value. Since ETCS was already an established design, providing the generic elements was relatively straightforward but adapting the design to the site-specific requirements took considerable effort. Included within these were:
- How to operate ETCS Level 2 in the areas concerned.
- Procedures for normal, abnormal, degraded, and emergency situations.
- Considerations for technical training, operations rules, local work instructions, sectional appendix updates, driver briefing and training.
- Interoperability requirements and compliance with Group Standards.
It begged the question as to whether the operating philosophy was driven by the technical solution or whether the technical solution was driven by operating requirements?
Testing was initially achieved by a simulation of the actual trackside hardware, first with an Alstom on board kit and then with Bombardier-supplied train equipment. Limited witnessing of the tests took place with Network Rail, ApBo, and ISA representatives present. Understanding the GSM-R radio link behaviour was, with hindsight, not covered adequately. Having a lab test facility in the UK within Network Rail would have been advantageous.
Dynamic testing
With equipment installed, thoughts then turned as to how on site, dynamic testing was to be achieved. Factors for consideration included:
- What is needed and who is responsible.
- Limited availability of possessions and track access.
- Virtual balise covers to allow balise installation (on the stage B section).
- How to test things once the Radio Block Centre (RBC) becomes operational.
- Having a safety justification to support the testing arrangements.
- Operational aspects including train length, train speed and acceleration / deceleration profile, stopping patterns and stopping locations, reversals within and outside the area.
- Multiple train messaging at the same time.
During the installation work, the positioning of compliant balise locations proved difficult because of point and crossing work, curvature, and derailment containments with Paddington station proving to be particularly troublesome. As a result, several derogations were needed to cover:
- Balise height.
- Fitting of balises on narrow curves.
- Balise proximity to TPWS and GW-ATP track equipment.
- Balise spacing (Hayes & Harlington bay platform).
- Train disconnection when leaving the area.
Transitions for trains entering or leaving the ETCS area and changing to TPWS / AWS needed to be robust and reliable. It was not intended to fit the Heathrow tunnels with TPWS but, to ensure continued train operation in the event of an ETCS failure, TPWS grids were installed at the entry signals. A further safeguard was to ensure the entry signal on to the Heathrow branch could only be cleared if the RBC confirms that the train is equipped with a working ETCS Level 2 system thus ensuring that any trains going to Heathrow had ETCS fitted. Temporary speed restrictions (TSR) were not sufficiently accommodated if trains entered or left the ETCS area too fast. This factor required the Network Rail TSR process to be revised.
Entry into service
Despite extensive testing, many problems emerged once the system went live. The commissioning took place over a weekend in November 2023. Initially all went well with the first two trains passing through and transitioning satisfactorily but the third train came to a halt as did the fourth, although the fifth was OK. By Monday morning, the railway was effectively not working.
With many trains grinding to a halt, the main problem was trains not changing to ETCS at Hanwell, just west of Ealing Broadway. A primary cause was found to be trains reversing at end destinations and associated change of driving cabs failing to re-set the system. It took time to bottom these problems out but, with hindsight, there was insufficient structure to manage, investigate, and resolve the faults. Basically, the lack of experience and competence with working on ETCS led to a lack of understanding on how the system was supposed to work. This was not confined to technical matters but also the operational readiness and comprehension of the failures which were occurring.
In such circumstances, it is human nature to engage in the blame game. The radio link is a critical element of ETCS L2 operation and it was easy to blame GSM-R coverage and functionality for some of the failures, most of which were found not to be attributable to that system. That said, 100% coverage is vital as any train stopped where radio signals are poor generates a big problem.
Achievements and lessons
This project was certainly a learning curve. It has however achieved:
- The installation and operation of ETCS Level 2 on the Heathrow Branch.
- The fitting of the Class 387 and 345 trains with ETCS equipment.
- The extension of ETCS from Airport Junction to Ealing Broadway.
- The planning required to further extend ETCS from Ealing to Paddington.
Although this has been an overlay scheme with lineside signals retained, around 70% of the expected benefits have resulted. The cost of the project tripled from initial estimates and changing the parameters meant a restart on four occasions. The overheads associated with hazard identification, safety assessment, and safety approval might appear to be excessive and all these activities do not come for free. Could there be an easier way to ensure a fit-for-purpose system without compromising system safety? Might more in house resources help fulfil these tasks?
It is important that the problems and challenges encountered on this project are shared for future ETCS schemes. The dissemination of information is vital as it could result in the same mistakes being made in different parts of the country. Some form of centralised knowledge base would seem sensible. ETCS has some critics as to whether it is cost effective but, within a few years, it will be the only show in town so achieving a full understanding of both the technical and operational issues is essential for future roll outs.
Thanks are expressed to Darren Dykstra from Network Rail and Simon Errington from Synergy Rail for sharing their experience.
Image credit: Stadler
