Signalling High Speed Connections Across Europe by Chris McCandless-Stone, Fleet Performance Manager, Eurostar
Chris briefly introduced himself and his railway credentials. He began his railway career at age 16 and already has 21 years experience. He is not a signalling engineer himself but clearly has a very good understanding of what is involved. His presentation was based on a Eurostar journey from London to Amsterdam looking at the various signalling systems across each country, beginning with a six minute video from the cab speeded up to cover that journey, with major place names and signalling system changes marked along the way. This proved to be a very good overview of the subject showing the different systems changes en route.
There is some overlap between countries as well as major and minor differences, although it is clear that most countries prefer to have their own variation of whichever system is being used at present.
Starting in the UK, he listed the signalling and power systems used ie ‘lights on sticks’, AWS/TBWS, KVB (Kontrole de Vitesse par Balises), TVM-430; 25Kv AC OHL, 750v DC 3rd rail, giving a brief explanation of each. For example KVB, used from St Pancras, the system continually monitors the running speeds – if the driver exceeds this by more than 5 kph, there is a warning, if speed is exceeded by 10 kph or more, the system will stop the train. Photographs showed the hardware installed such as the balises between the rails, and the electronics alongside the signals. The balises are only active when the train is near or passing over and they are very reliable. There is a mix of systems in use and an electronic decoding system with some limited information as part of the cab display so that the driver is aware. KVB is programmable but is fixed on Eurostar locomotives. We were shown a photograph of the in-cab display and a diagram to help illustrate the verbal explanation.
On the same part of the journey the TVM (Transmission Vole Machine) picks up just outside St Pancras using in-cab signalling to replace lineside signals. A very clear explanation – suitable for the not so technically minded – described how this works, the line speeds (up to 319 kph) and the various levels of TVM with the most up-to-date allowing a continuous speed curve. Technically, the driver does not need to look out through the windscreen and can drive on the cab information only. He/she can also do shorter diversions as long as the TVM is switched on.
All the signalling systems in use in the UK were covered before moving on into France where there is a different mix of signalling systems. This means that the electronics in the cab have to change over and the driver needs to be very aware of the differences and what to expect including Wiegand sensors for tachometry attached to the axles. These are very reliable passive sensors as long as the are not detached on the wheel lathe during maintenance! At this point Chris described the back-up and fail-safe systems with three sets of processors. Between them these can work out what is going on and the in-cab systems can continue to function even if one processor develops a fault. At this point Chris listed the signalling and power systems operating in France ie ‘lights on sticks’, BRS (Brosse Repetition Signal - used on SNCF classic lines)/RSO, KVB, TVM 300, TVM 430, 25Kv AC OHL, 1500v DC OHL, and briefly described how these work.
Moving on to Belgium, there were further changes with different systems providing similar functions with ‘lights on sticks’, Memor (similar to AWS), TBL 1, TBL2, TBL1+ (approximating to KVB), and ETCS (European Train Control System). Power here is 25Kv AC OHL or 3Kv DC OHL. Each system was explained at just the right level of detail to be interesting without being technically overwhelming, showing how each works and what it does. In Holland there are ‘lights on sticks’, ATB (classic Dutch signalling), ETCS, 25 Kv AC OHL, 1500v DC OHL. Holland (or the Netherlands if you prefer) was the first European country to adopt ETCS.
What becomes clear is just how much there is for the drivers to learn and, to help illustrate, we were shown some interesting photographs of the extensive technical hardware in each Eurostar train that ensures a smooth transition between systems. Suffice it to say, it is complicated kit and there is a lot of it, beautifully illustrated by Chris’s photographs. The Class 374s have ETCS/TVM and are more complex, as shown by the diagrams, although it is smoother for the driver. The front ‘nose’ is full of electronic hardware. We were given an overview of the driving cab with explanations of what the displays represent with the comment ‘the train does it all for you’. However, the drivers need to be aware of, and familiar with, all systems encountered; so a great deal of training and knowledge is required for them to be able to drive their passengers safely throughout the journey, with most of them completely unaware of the complexities involved and the quite remarkable electronic and technical achievements that make it all possible.
For the last part of the presentation Chris spoke of the future digital railway using ERTMS (European Train Management System)/ETCS. This has been developed by 8 European railway nations in collaboration with the EU, involving consultation with several railway equipment manufacturers with a view to harmonising systems instead of having several different ones. Once fully operational, it will probably be the most effective signalling system in the world giving a significant advantage.
After the break, we were treated to a short video of Chris’s ‘baby’ ie 3308 – now at the National Railway Museum (NRM) in York. This brief part of the presentation included the first HST (High Speed Train) in the UK with Chris and Bob Gwynne of the NRM, talking about the history and earlier dreams for the future connecting the UK and Europe.
Questions and answers followed including track circuits, axle counters, passengers feeling safe with a future fully digital railway, when different systems came into use in the various countries en route, pantographs, and equipment and materials amongst other things.
The vote of thanks highlighted the amount of equipment packed into the cab, thanks that Chris had clearly explained all the acronyms instead of just using them, and thanks for an exciting and fascinating insight into the similarities and complexities.