More Accurate Simulations with Less Effort

IMPACT™ incorporates a powerful timetable simulation tool for route level modelling and simulations. This tool uses the existing network layout as a basis but allows the user to amend and save alternate layouts.

This significantly reduces the time, cost and effort involved in building network layouts and allows berth level actual performance data to be used as a basis for simulations, improving accuracy .

The base performance data used for simulations is analysed for a wide variety of factors including:

• Schedule service type (AM / PM Peak and Off-Peak)
• The impact of interference caused by other trains
• The impact of identified performance events.

This allows the impact of these factors to be identified and incorporated into the simulations.

Base data for new or revised network sections is created by the system and includes the natural variation in performance that can be expected from driver behaviour and other factors.

Using berth level statistical distributions drawn from actual data, rather than pre-selected statistical models improves the accuracy of the simulations by:

• Removing the inaccuracies introduced by fitting standard distributions to the data.
• Introducing the natural variation in berth level running times that occurs in actual running.

Variation in both origin-departure punctuality and route-entry time (for trains not originating on-route) are also incorporated into the simulations.

The application incorporates a timetable-editing tool that allows changes to be made to an existing timetable in CIF format quickly and easily.

Performance events can also be incorporated into the simulations either through the use of historic performance distributions or in a more deterministic manner. This allows the impact of a specific event to be modelled.

Using a Monte Carlo type simulator allows the user to run the simulation any number of times. Thus thousands of simulations can be run providing a realistic “spread” of outcomes and the performance delivered by a timetable assessed at different confidence levels.

This allows better informed decisions to be made to balance the competing pressures of capacity utilisation and service performance.