The challenge
Avanti West Coast have been exploring refinements to their timetable, to help accommodate future growth. In doing so have designed a number of potential alterations focusing on re-timings and stopping patterns. One of the objectives of these changes is to improve service performance on the WCML.
Timetable design is a collaborative process, involving other train operators and Network Rail. Due to the interactions between train services, any changes to timetables for one operator risks unexpected consequences on performance for other operators. Due to everyday variations in service timing due to minor or significant incidents, services might end up conflicting with each other, causing delays and lateness for passengers. Timetable changes are therefore only agreed after discussion of the possible risks with all parties concerned.
It is a difficult challenge identifying the risks of making changes to how parts of a complex system interact. A vital part of this challenge is using the knowledge and experience of stakeholders who understand the rail system, shared through a discussion of the possible outcomes. SaviRPM agent-based modelling of a railway system provides insights for these discussions.
The results of modelling are presented to stakeholders using interactive visualisations, helping them identify the risks of changes in timetabled services over many modelled days. Every day is different, from good days to bad days, with random delays to services causing different interactions.
Modelled results provide evidence of possible impacts when services are ‘out of path’, interacting differently to the planned timetables. This provides stakeholders with information about the quantified risks to performance when timetables are changed.
“Working closely with Risk Solutions means that we are now better equipped to continue doing modelling and analysis independently, to discover further insights to improve performance through better timetable design” Andy Smith, Senior Long Term Planning Manager, Avanti West Coast
What we did
We modelled a baseline (current) timetable using SaviRPM, simulating typical train journeys over 100 days, for Avanti and all other operator services on the West Coast Main Line. We introduced typical delays to the modelling, representing good days and typical days. This was repeated for an option timetable which had some carefully designed alterations to stopping patterns and timing for Avanti West Coast services, designed to improve performance.
Working closely with timetable planners we explored in detail the modelled results looking at the performance of Avanti West Coast services and possible impacts for other operators. The team compared the two sets of modelled results and measured changes in performance by service group and location, providing a key tool for Avanti west Coast to engage with industry partners to explore future timetable options.
“Working closely with Risk Solutions on this project has been very rewarding, our collaborative approach has vastly improved our understanding of the SaviRPM software. Our knowledge of the timetable structure combined with their knowledge of the software made deep level analysis of results much more effective, and allowed us to explore the art of the possible when it came to next steps” Ben Kelly, Strategic Timetable Development Manager, Avanti West Coast
What we found
The modelling work showed that:
- Performance modelling can be used to confirm timetable design hypothesis, quantifying potential benefits and impacts, and identifying ways to further refine proposed timetables.
- The proposed changes to the timetable are likely to help meet Avanti’s objectives.
- Presenting the quantified risks and benefits using SaviRPM’s visualisation tools helped to inform discussions with other rail stakeholders. They were able to focus together on the issues that were more likely to influence performance.
- The analysis identified further timetable design work to be done. There were some services and locations where additional changes to timetable design might result in performance benefits, to be tested with further modelling.
Avanti West Coast are now able to continue modelling with greater confidence that modelling work can contribute significantly to efforts to improve service punctuality for passengers.
“Analysing the detailed model results with Risk Solutions has been extremely useful. We are now able to quantify the benefits of our proposed timetable options and target and refine these to help present the case for change to Network Rail and our partner operators” Andy Smith, Senior Long Term Planning Manager, Avanti West Coast
Using SaviRPM
We setup SaviRPM to model around 6,400 timetabled services with over 41,000 station stops, covering the entire West Coast Main Line from Euston to Glasgow and Edinburgh, including surrounding areas; Birmingham, Manchester, Liverpool and North Wales. This represents approximately 1/3rd of the UK network, a wide area selected to represent typical interactions between services over their entire journeys. The model was calibrated using an iterative process against over 5 months of real-world train timing data, representing a mixture of typical summer and autumn incidents that might affect service performance.
We explored the results using our powerful interactive visualisations, allowing us to focus on the areas of poor performance and investigate interactions between services, and the impacts for all operators’ service groups.
“Working side by side in real time has given us confidence in the Savi workflow and will enable us to carry out our own modelling in a more informed way” Ben Kelly, Strategic Timetable Development Manager, Avanti West Coast
The modelled results
Summary performance analysis: Arrival performance for a target group of services over 100 days showed that the changes in the option timetable are likely to deliver significant improvement in performance of 5% in a particular service group.
These example charts show a summary of the station stop punctuality for 100 simulated days (the thin rows). The colours represent arrival within 1, 3, 5, etc minutes of timetabled times. The values quoted are the average (median) arrival performance represented by the middle blue line. The blue band shows the interquartile range of results, representing the variability between days as services interact in different ways.
Detailed location performance analysis: The analysis included considering service interactions at specific locations, providing evidence that the timetable changes were delivering the improvements expected. This example chart shows an hourly repeating pattern of services at a junction whereby other services join this section of route and then following in close succession to a key station.
The green shaded area presents the interquartile journey lateness of each service from 100 simulated days (the 50 journeys closest to the average lateness). The planned (timetabled) journey is shown as the left-hand edge of the grey shaded area. This chart is showing the typical variation in journey lateness from day to day, removing very good and very poor journeys. The wider the green shade, the more variation there is in typical lateness. The green line is the average (median) journey lateness.
In the baseline simulated days (pop out chart) these green shaded areas are wider and overlap at this junction, for the two labelled trains of interest. This shows that in the option there is likely to be more separation between services, resulting in fewer conflicts and delays, and less lateness with better performance for both trains.
“The visualisations of modelled results are excellent, and help us tell a clearer story, making conclusions more accessible to others” Andy Smith, Senior Long Term Planning Manager
We would be delighted to hear from you if you are interested in finding out how SaviRPM could help you understand the drivers of good performance. Please get in contact.
We have published more information about SaviRPM and some case studies here: SaviRPM demonstration