Boxing clever

The headline announcing the closure of over 800 signal boxes is bound to attract attention. Even more so when there will be only 14 remaining. But what is behind all of this? What is Network Rail attempting to achieve by the wholesale closure of almost every signal box on the network?

Talking all this through with Steve Knight, Network Rail’s Head of Operations Development, it’s obvious that there’s some serious thinking behind the headline. It’s not just about the closure of boxes. In Network Rail’s words, “It’s a planned, co-ordinated and accelerated programme of signalling renewals with control moved to fourteen new centres that will feature new automated traffic management systems and software.”


Right, so what does this mean and why is it on the table? It’s time to look at the current situation and also a bit of history.

There are, very broadly, three types of signal boxes. There are the 19th century structures with mechanical levers. These are frequently single-manned boxes in rural locations. All in all there are about five hundred in this category. They often control access to and from a branch line. If they’re unstaffed, then the branch is shut and this predetermines whether late evening or early morning trains can run.

In the 20th century, the panel box appeared from the 1930s onwards followed much later by the IECC (Integrated Electronic Control Centres) and there are a total of around two hundred of these. Some of these too are single manned. In recent years the Rail Operating Centres (ROC) have been built which, like the IECCs, have modern ergonomically designed working environments and VDUs (banks of computer screens). There are just eight of these at the moment with a further six planned.

High unit costs

The exercise isn’t a witch hunt against the mechanical boxes on the basis that mechanical is bad and computers are good. It comes down to economics and a desire to improve the service for train operators. Typically, the mechanical and early boxes control relatively few SEUs (Signal Equivalent Units)… one signaller in control of just a handful of levers. In fact, 18% of Network Control absorbs 49% of operating costs. At the other end of the scale – the area of the ROCs – one signaller can control 200 – 300 SEUs. In these centres, 12% of Network Control absorbs just 4% of Operating costs.

The challenge for Steve and his team is how to address the issue of high unit costs at the same time as acknowledging that some of the older, simple equipment is very reliable – at the moment. But the party doesn’t go on for ever though. Much of the signalling stock will need to be renewed in the next thirty years. Couple with this the desire to offer improved train operation (capacity/performance/passenger information), and a need to drive down operating costs and what has emerged is a strategy for an accelerated renewal policy along with another to control the network more effectively.

This all might seem a little ‘blue skies’. But it’s not really. There is no delving into technology that doesn’t exist at the moment. There’s no reliance on signal equipment that has yet to prove itself or even be invented. Steve’s strategy is based on existing technologies and existing traffic management capabilities.

Closure rates

Returning for a moment to the box closure proposal it’s worth remembering that closures have been going on for at least the last 110 years. In 1900 there were 10,000 boxes. After Beeching there were 5,000. BR had a relentless programme that closed around 100 per year. In fact, in the last 10 years before privatisation, BR closed more boxes than exist on the network at the moment.

Then, abruptly, it all went quiet after privatisation with only 10 closures a year. The current Operating Strategy is aiming to close about 50 per year – just half the rate of the closures under BR, quite a few of which will be within the working memory of many on the railway.

Predictive modelling

So, with the aim to centre train control on just 14 buildings, what are the possibilities? Cost savings are one obvious result. The other Holy Grail is the ability to concentrate information from the network so that it will be feasible to model the running of trains in real-time and also to predict the behaviour of trains far more reliably than at present.

What traffic management systems (TMS) are used to predict train behaviour at the moment? Well, to be blunt, there aren’t any. There is extensive reliance on experienced humans who are very good at what they do. But it can be argued that the very powerful skills they use in their predictions could be of more use in the management of evolving situations. Up for grabs is the ability to reduce reactionary delays. This is the time lost between an incident occurring and the normal timetable being restored. At the moment, this accounts for 50% of all industry delays. Laudable though it may be to invest in reliable rolling stock or infrastructure this 50% just doesn’t go away. Ten million minutes roll up every year and it has remained stubbornly static. Experience gained in other parts of the world suggest that a 20% reduction in reactionary delays is possible.

Effective communications network

It’s an uncomfortable fact for signal engineers and control software system writers that they can’t achieve anything unless there’s an effective communications network between the centres. Plonking fourteen buildings down around the country will be a waste of time if they are not able to be sat smack on the top of a large cable linking them with every other part of the network and indeed every other centre. Steve is confident that this too is achievable and in most cases already in position.

The linking of buildings using the national secure telecoms network gives some interesting possibilities. As none of them will have conventional panel displays – the sort of thing that is dedicated to a particular stretch of line – it is possible for any centre to control any part of the network. With VDUs it could be possible for them to show a local layout and then, if an adjacent box is ‘out of action’, the layout for a remote location. This ‘great idea’ runs into practical difficulties if the operators of the centre are unfamiliar with the new layout. As Steve says, “Much of all this has to do with people rather than an addiction to technology”.

Traffic management systems

Although seemingly futuristic, the traffic management system uses proven software and processes from across the world, which will be adapted and prototyped in new centres with industry colleagues and supplier partners. It will be highly automated and will largely run itself.

It will include real-time planning/prediction and resolution of movement conflicts. This is done by optimising the use of the existing infrastructure to enable more capacity without impacting performance. And as a result it will include a single operational information system, providing real-time information to passenger and freight customers particularly during times of disruption.

It’s worth remembering that none of this is Signalling. None of this impacts on the interlocking. It gathers information from the signalling interlocking and uses this as a basis for its calculations.

Action plans

These are the ideas – what are the plans?

There are three things to do. First of all build the new operating centres. These unlock operating efficiencies. Steve’s view is that, “We’re about creating an environment where you’ve got all of the bits of running a railway you need in the same place; signalling control, electrical control and the train company resource. You will not succeed unless all the interfaces are seamless.”

As far as the location of these centres is concerned Network Rail has adopted a pragmatic mix of what they’ve already got, where they aspire to have locations in the future, and they’ve taken into consideration things like use of existing buildings, flows of train traffic, route customer boundaries. Undoubtedly, people will say that these will change. They can change but they didn’t come about by fluke either. They’ve come about though patterns of travel, historical logical boundaries – and these arguments become less relevant all the time the centres can talk to each other.

From a technology point of view, these debates about boundaries are less relevant. What is important is the people aspect.

Modular Signalling pilot schemes

Secondly there’s the accelerated consolidation – the removal of mechanical systems and the re-control of power boxes.

Up to now Network Rail would have deployed the same signalling renewal solution on a mechanical route as they would have on a main line. Modular Signalling is a slightly simpler method of signalling for secondary lines and this technology will be used to allow mechanical signalling renewals to be consolidated into the new centres.

There are two Modular Signalling pilot schemes today. Crewe to Shrewsbury and Norwich to Ely are both due to be commissioned in the next year.

“We can create a case to replace mechanical boxes or re-control power boxes earlier than their renewal date with an aim to get about 80% of the network complete in the next 15 years. It is an acceleration of the renewal process. Undoubtedly, mechanical boxes would carry on, but they incur disproportionately high annual costs in the process and can’t interface with Traffic Management technology.”


Finally there is the introduction of the traffic management technology which unlocks output capabilities. There will be a nationally specified TMS that will be independent of interlocking technology. So, for example, it will be able to talk to an Invensys interlocking or a Siemens interlocking or an SSL interlocking. And this independence allows the TMS technologies to be refreshed more frequently than the interlocking technologies.

Network Rail is talking to six suppliers – Signalling Solutions Ltd, Thales, Ansaldo, GE, Hitachi and Invensys – and aim to build two or three prototypes before next summer.

Steve points out that, “This is about making sure that our data can be integrated into their products. In discussions we need to understand what we want from traffic management and what they are capable of supplying.”

There are existing products which are operated in other parts of the world. They largely automate the routine stuff so allowing people to manage the emerging problems.

“We don’t have predictive capability. We’ve systems which say where trains are and how late they are, but nothing to say where they will land up and what to do about it.”

Building a prototype will give a better idea of the technology and also the training and people side. The prototype will probably centre on a workstation rather than being built into a resignalling scheme.

Although the headlines focus on the 800 signalbox closures, there’s much more involved in this project. Technology and communications have advanced to a point where everything is possible. And to a great extent, if it’s possible to do today then, sure as eggs, it’ll be possible tomorrow – and possibly easier. Microprocessors will come and go, manufacturers will come and go, but the basic architecture of the new operating system will persist for decades to come.