Railway Performance Society Magazine - Milepost
Driver Advisory Systems
RPS Meeting Report Driver Advisory Systems
At the 5th November meeting in London, Ian Mitchell from DeltaRail gave a most interesting and well-presented talk on the motivation behind the development of modern Driver Advisory Systems (DAS) and current plans for implementation for main line train operation in the UK.
The basic objectives of DAS are to optimise train running and overall capacity, whilst at the same time saving traction energy through the full utilisation of any un-needed allowances built into WTT schedules. Generic strategies for more energy-efficient driving incorporated within DAS might include i) running at reduced maximum speed to reduce the energy required in accelerating and to minimise aerodynamic losses (accelerate-cruise-brake), ii) utilising stored energy to save traction power and minimise braking losses (acceleration-coast-brake) and iii) limiting the acceleration rate to minimise traction losses or peak power demand (reduced acceleration-brake). There are a range of possible system architectures. In the more complex, all processing might be done interactively in a main control centre with the results simply transmitted for presentation to individual drivers. More basic and probably in the near future the most viable are ‘in-cab’ stand alone systems (which may either be portable hand-held devices, permanently installed discrete units, or software integrated into already existing train management systems) which select the most appropriate driving plan from a number of pre-programmed options. The information presented to drivers may be prescriptive (eg Notch 4 now, Coast now), goal setting (eg cruise at an average of 75 mph on the next journey leg), provide feedback for driver action (eg 15 sec ahead of schedule at the last timing point), contextual (eg gradient profile), or even signalling based (eg with information about how trains in signal blocks to the front and rear are running). There is at present no general consensus as to how information can best be provided, and example displays were shown of various currently available commercial products with outputs ranging from comprehensive full screen graphics to simple textual messages about speed and timekeeping. There are however clear issues with all DAS in their relationship to primary safety systems, the effect on drivers viewing the track (risk of distraction and head-down driving) and the frequency at which information or advice should be updated. Simulations and trials show however that DAS have the potential to provide significant energy savings (typically 15-27%), to maximise capacity by optimising traffic flows to avoid conflicts at junctions, and to increase safety by having fewer trains brought to a halt at red signals (and ensuing risk of SPADs). Whilst not going as far as fully automated train operation, there could be a future role for enhanced DAS in providing intelligent ‘cruise control’ through speed and coasting management when running under clear signals, reverting back to driver control when over-ridden or on the approach to junctions and stations.
Courtesy of First Group, a preview was given of the planned driver set up and display screens of the forthcoming implementation of the TTG in-cab ‘Energy Miser’ system on FGW HSTs – all very much designed not to distract the driver when running at high speed (a typical display reading might be ‘Advice speed 110 mph. Coast in 20 secs’). Driver advice would only begin two miles after leaving a station and there would just be an ‘Approaching next station stop’ message two miles before the next stop (along with the due and expected arrival time). The system will also cease providing advice if the train is over 10 minutes behind schedule, if the GPS position signal is lost, or if ‘off profile’ running is detected (for instance when encountering adverse signals, if diverted onto the slow lines, or if braking for emergency speed restrictions not known about by the DAS).
Interesting times ahead to see how all of this impacts on actual train running and performance.
David Stannard
Details of the presentation at:
http://www.irse.org/knowledge/publicirsenews/IRSE%20News%20151%20Dec%2009.pdf