Almost by definition, there has to be a wealth of talent within Britain’s universities, some of it hopefully studying engineering and technology. The mind-sets of the young are uncluttered by past practices and thus able to think up new ideas that would be dismissed out of hand by those of us who are steeped in the traditional way of doing things. Can this innovative thinking be put to good use in the rail industry? Professor Roger Goodall from Loughborough University, and a recent Past Chairman of the IMechE Railway Division, gave a fascinating insight in a recent lecture to the IRSE into how this is being achieved.
The government is encouraging industry in general to be more innovative and the Department for Transport has wanted a partnership with the Research Council to look specifically at opportunities within rail. This has resulted in the Rail Research UK Association being established, a body being funded in part by the Rail Safety and Standards Board (RSSB) and Network Rail, tasked with seeing whether anything can be done to increase railway capacity without the expensive options of building more trains or enhancing infrastructure.
The remit is to go a step beyond what the industry is currently doing – to think the unthinkable and to challenge the rules. Whilst capacity on plain line can be readily calculated, adding ‘fixed nodes’ such as stations, junctions, crossovers and level crossings, can quickly reduce the theoretical capacity that is available. The general guidance is to run a train service that is between 60-70% of the calculated capacity and is set down in a
Capacity Utilisation Index (CUI) but can this be improved? Any increase will involve a trade off between reliability, delay and capacity.
Five grants were awarded in 2011 to different Universities to investigate five separate radical approaches. Some of this work is completed and some is ongoing. Each one is described here.
This project has looked at overcoming capacity constraints by optimisation of train movements through ‘nodes’ (hence the acronym!) and has been studied by the University of Southampton. ‘Pinch points’ at Pirbright Junction and Southampton Airport Parkway were initially studied but neither of these presented a significant challenge so the investigation moved to the section of East Coast main line (ECML) between Huntingdon and Grantham, concentrating on the important junction at Peterborough and particularly the cross country services on the Lincoln – Peterborough – Ely corridor.
A ‘job shop’ model (each train
being a job) was produced searching for relationships between train types and characteristics, track sections, train movements and arrival/departure times, but without any change to the operating rules or track layout. The model potentially showed that an additional 14 services could be operated on the cross country route but that only a small increase would be possible on the ECML. The latter is limited by the number of tracks available between Peterborough and Huntingdon.
The model is capable of considering the impact of train service perturbations at Grantham and Huntingdon and the effect these would have on the Peterborough complex. It also showed that with higher speed points and some changes to the switch & crossing layout, many more capacity improvements could be obtained.
Ever mindful that safety must be maintained in any capacity increase initiative, Newcastle and Swansea Universities, assisted by Invensys Rail and a Japanese Institute, have been assigned a project to produce a ‘push button’ check which would verify whether or not changes to control tables or signalling designs are safe. The model is based around a standard double junction and already suggests that, by changing the control table, an additional train every six minutes can be accommodated without compromising safety. This can be further improved once a full ATP system is installed such that rules can be adjusted accordingly.
This is an on-going piece of work and will use Carlisle, Leamington Spa and the Thameslink route as trial sites.
Dynamic Responsive Signal Controls
Closely aligned to the driver advisory systems that are being introduced, this project is a study by University College London to harness real time data and communications obtained from the operational railway to try and get trains into the right place at the right time and at the right speed so as to avoid conflicting movements and any associated acceleration or braking of trains. The key output will be the optimised ‘trajectory’ of trains based upon trains providing position, speed and planned trajectory (routing) information and control centres providing state of the network, planned signal changes and projection of trajectory information.
From these two elements, optimum train paths can be calculated in a real time situation to promote capacity increase, whilst at the same time taking into account resilience and timetable recovery. It is recognised that automatic train operation (ATO) would be needed in order to yield the maximum benefits but, even with manual driving, the results show that significant gains can be achieved.
Edgware Road on the London Underground, with its flat junction and four platforms, is the case study to see whether changes to the operational margins can improve both performance and capacity.
Fault Tolerant Rules for Train Control
This project really does test the boundaries of ‘normal’ train control operation and is being carried out by the University of Salford with assistance from Leeds University. The basic thinking comes from the preconception that road users (and to a certain extent pilots of aircraft) are constantly anticipating the situation ahead and making adjustments accordingly. The railways have traditionally been cautious in how trains are controlled when approaching a junction or station and methods of reducing speed using approach control signal aspects are the norm. As a train nears a junction, the controlling signal will be held at red until firstly, the route is proven clear and secondly, the train speed is appropriate for the route to be taken.
This project examines a scenario that allows a train to approach the junction or station at a much higher speed on the basis that the intended route will be cleared successfully
in the vast majority of instances. If on a rare occasion the route does not clear, then an ‘escape path’ must be available for the train to take if the speed is such that the controlling signal would be passed at red. Two examples would be:
» a train is approaching a terminal station and is booked into a specific platform. If the platform remains occupied and an alternative, non conflicting platform was available, then the train would be routed into that;
» a train is nearing a junction and is due to take a diverging route across an opposite direction track in the process.
If safe passage across the junction does not materialise, then the train would be routed straight on if unable to stop at the controlling signal.
Some of this will make traditional signal engineers and operators squirm but is it so unreasonable? Providing the safety of the signalling system is not compromised and the occurrence of such incidents can be proven
- as extremely rare, then valuable time can be saved and capacity increased. The ongoing problem of getting the train back onto its required route and the disturbance to other train services in the process will need to be weighed up.
REPOINT – Redundantly Engineered Points
This project, being championed by Loughborough University, looks at the reliability of current switch and crossing technology and suggests how point performance can be improved, thus improving utilisation and providing increased capacity. Currently, points are considered to be unsafe unless proved in a certain position. When point correspondence cannot be assured, then restrictive measures have to be put in place that will adversely impact on the train service. To overcome this situation, switches can be designed with more redundancy, invariably adding additional components and causing extra cost. Can there be a different approach to eliminate failures at these critical nodes?
A design which uses ‘stub switches’ to give multiple routes from a single switch end is under development. Because of pending patents, details are scant at this stage. There should be many advantages but equally there will be drawbacks – how to lock rails in position and a potentially large rail gap. The university believes it has solutions to these problems and the outcome would be reduced switching times and elimination of the ‘out of correspondence’ state. The goal is to make points as reliable as plain line.
Two case study locations, HS2 and Waterloo Station throat, will be progressed so as to compare the impact on two very different rail scenarios. This is revolutionary in concept but so was the aircraft ‘fly by wire’ system when originally devised and considered unthinkable by the air industry authorities at the time. Nowadays it is very much a norm and no modern aircraft would use anything else. Such is the acceptance of progress.
A slow process?
All five projects started as ideas for improving capacity but the work to date has shown that other benefits will result, some of which are more significant than easing the capacity constraints.
Getting acceptance is likely to be a slow process and the Universities are under no illusion that there will be considerable but hopefully measured opposition. History shows that the mainstream railway engineering departments were at best always suspicious of ideas that BR Research sought to impose on them and at worst openly hostile. There were successful examples that shone through, such as the development of SSI resulting in excellent cooperation between research, engineering and industry, but even that had a hard core of die-hard signalling engineers who opposed it on the grounds that computers were inherently unsafe.
The structure of the UK rail industry has moved on and it is re-assuring that participation from signalling companies is happening in some of the current projects. The onerous process of achieving safety approval will have to be gone through and it can be foreseen that the safety fraternity will be pedantic to the extreme for some of these ideas. A reining in of their freedom and responsibilities might have to be called for.
So – exciting stuff and something that will be watched with interest. The real benefit could well be the much closer co-operation between universities and the real world of practical engineering and operations.