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Conflict Checker

The Conflict checker in TrenoLive serves mainly as a control instrument to check created timetables for potential errors on an organisational, a macroscopic or a microscopic level. A number of different algorithms are implemented to reveal conflicts or planning mistakes at an early stage. All conflicts found should be checked and resolved. However, it is possible - by conscious decision of the planner - to ignore some results of the conflict checker.

The check can be limited geographically on area or corridor and temporarily from [date] to [date]. The geografical limitation is exclusive, so either an area or a corridor can be checked, but never both at the same time. The check is covering the full calendar dates selected, from 00:00:00 to 24:00:00.

Trains with departures after midnight (>24:00:00) will be checked only on the calendar date after their operating day.

The conflict checks can be repeated regularly by activating "Repeat 15 minutes after last scenario change". This repreats the check if for 15 min no user has made modifications to the timetable in this scenario. Otherwise, a manual repetition of the calculation is possible by clicking on the "rerun" button in the results list.

Types of algorithms available​

The conflict checker consists of:

  • Clash in track (Two trains planned on a line track at the same time)
  • Clash in OCP track (Trains planned on a station track at the same time)
  • Short track (Trains stopping on a station track that is shorter than the trainset length)
  • Short track sector (Trains stopping on a station track sector that is shorter than the trainset length - this is not always a problem)
  • Turnback time (A turnback with planned stop time (including stop margins) shorter than the minimum turnback time of the trainset)
  • Platform length (Passenger trains stopping commercially on a platform that is shorter than the trainset length)
  • Possession on line track (Train planned on a line track at the same time of an active line track possession)
  • Possession on station track (Train planned on a station track at the same time of an active station track possession)
  • Check turnaround connections (Checks for missing, invalid or unbalanced connections)

Further the Conflict Checker checks the timetable against user-inserted thresholds (minimum/maximum) for example on:

  • Run time in s
  • Dwell time in s
  • Speed on edges in km/h

Planning rules violations are revealed by the checker for:

  • Headway time violation
  • Junction margin violation
  • OCP track reoccupation time They are checking against user-inserted thresholds, too, but now for short headways or platform/track reoccupation times in stations.

In some cases it might be necessary to check the timetable for missing information. Available are:

  • Missing track
  • Missing platform

A check for train number uniqueness is also available, checking the timetable, if trains with the same train number are active on a calendar day. The train number uniqueness checker is designed to exclude train numbers repeating in a reasonable time span (>23 hours), to not give false-positive results.

Other planning mistakes such as inconsistent or impossible itineraries can be detected by using the RTC function, which is checking the microscopic itinerary of the train and also checking running times. A full and complete feasibility check of the timetable is only possible with a simulation, using stochastic variations. For more info go to the simulation page.

The most detailed results - other than a full simulation - are obtained by the Micro conflict checker. This algorithm checks the blocking times of trains including planned margins on each train detection section of the microscopic infrastructure model. It reveals conflicts reliably and with precision in complex nodes and stations with many conflicting itineraries. To execute the micro conflict check it is necessary to calculate the RTC of all trains on the corridor/sim area beforehand. For the micro conflicts the automatic repeat 15 min after the last change is not advised, as the RTC does not recalculate automatically during this process.

The results of the conclict checker allow to open the train editor of the trains involved in a conflict by double-clicking on the train number. It is possible to download the results in an excel table.

How to use the conflict checker​

  1. The conflict checker should be a regular tool in the planning process. Some checks will be used more often than others. The most basic checks are:
  • Clash in track
  • Clash in OCP track

These two identify errors ("clashes") in a timetable on a macroscopic level and can be usd without any further preparation.

  1. Other basic checks involve user-defined planning rules violations:
  • Headway time violation
  • Junction margin violation
  • OCP track reoccupation time

To use these the specific planning rules need to be defined in the respective tabs. It is important to remember, that the checks are still calculated on the macroscopic level.

  1. Short track, Short track sector and Platform length require an accurate setup of the macroscopic model and the trainsets and work reliably if this information is kept up to date.

  2. The turnback time check should be used if trains have planned turnarounds in the timetable. TrenoLive identifies turnbacks automatically based on the Edge tracks in the train editor and the station layout in the macroscopic model. The turnback time checker adds further value if connections, and therefore a detailed vehicle roster, is defined already. It will highlight connections without sufficient turnaround time. For this check to work properly, the trainset requires an up-to-date Minimum Turnaround Time (MTT).

  3. The last check to be performed is a stochastic simulation to approve the timetable as feasible and robust in normal operation. The simulation is described in further detail in a dedicated page and the trenissimo manual.

All other checks are optional and should be used when needed.