Performance Modelling
RailSys™
RailSys™ is a railway timetable/infrastructure simulator developed initially by Hanover University and now developed and marketed by a spin-off company RMCon. It has been widely used for a number of years in Northern Europe and also in Australia.Other software packages that have traditionally been used to undertake performance modelling include VISION or MERIT (from AEA Technology Rail), Opentrack, or RailPlan. In comparative analyses undertaken for the DfT/SRA and by Network Rail, RailSys™ has always been found to be the most advanced - primarily because it has the capability to run large numbers of simulations at a detailed level without analyst intervention (because it has the most sophisticated Automatic Route Setting built into it of any tool on the market at present). RailSys™ has now become Network Rail's preferred timetable and performance modelling tool.
RailSys™ uses a very detailed view of the railway infrastructure, including track layout,gradients and signalling (down to individual signals and track circuits).
Timetable Editor
RailSys™ contains a powerful timetable editor, which enables the analyst to create or retime trains and then assess any conflicts created. "Drag and drop" functionality allows the analyst to rapidly perform "what if" analyses. The current version of RailSys™ provides automatic guidance on technical conflicts (for example, where signalling headways have been infringed) but requires the analyst to manually check for Rules of the Plan compliance.Nominal Timetable
The nominal timetable simulator can be used to highlight direct conflicts between trains as a result of inaccuracies or lack of precision in the scheduled timetable and their consequences. In this mode the simulator is run without adding delays. Conflicts that will be identified include headway conflicts, double occupation or crossing conflicts as well as any incidence where a train driver will see and react to a restrictive aspect signal.The nominal timetable simulator is typically used for:
- Running time analyses for future infrastructure and rolling stock
- Headway calculations and capacity analyses
- Feasibility studies where performance prediction is not immediately required, for example timetable construction reflecting future infrastructure
- Modelling and testing of current and future timetables for conflicts
- Certain types of what-if-analyses, for example the impact on the timetable of possessions
Multiple Simulation
Delays on railways can be replicated reasonably reliably by using multiple simulation techniques. The modelling work starts by setting up delay distributions representing primary failure rates at locations in a study area and at the entry points to the area. These distributions are then sampled using the Monte Carlo statistics principle. The multiple simulation tool within RailSys™ creates a number of timetables to be perturbed by overlaying these samples of primary delay. Simulating these timetables gives punctuality results for in effect a range of possible operating days with different primary delays and hence different secondary delays.The number of timetables required in a multiple simulation run to provide a good level of likelihood that the overall average delay reflects reality can vary between 30 and 250, depending on the nature of delays in the study area and the complexity of the network and timetable. Higher levels of congestion usually require higher numbers of runs as overall delay levels can be more sensitive to small changes in primary delay.
The Multiple Simulation tool can be used for:
- Bottleneck analyses of infrastructure and/or timetables
- Understanding the knock on impact of delays
- Evaluating robustness and quality of the modelled system
- Comparing and evaluating different infrastructure and timetable versions
