In operational service, deviations between the timetable and the actual transport service occur regularly. These deviations are mainly reflected in delayed arrivals at stops, but may also include skipped stops or extended dwell times. Operators and public transport authorities have a key interest in systematically identifying the causes of recurring timetable disruptions. The aim is to identify and specifically address the root causes as part of a disruption source analysis.
Public transport vehicles transmit their arrival and departure times with precise timestamps. This means that the run and dwell times for each section and each journey can be tracked exactly. This data is usually stored in an ITCS (Intermodal Transport Control System) or can alternatively be obtained from simulations for planning purposes.
In Visum it is possible to store and analyze such data. The following steps are necessary for this:
1. Input and storage of the measured operating data
2. Creating an actual timetable from the measured data
3. Comparison and evaluation of actual and target timetables
Input and storage of the measured operating data
Input attributes are available at the vehicle journey items to save such data in Visum. These include:
- Measured arrival and departure times
- Post run times
- Dwell times
- Information on whether a planned stop has been served
Arrival times, departure times, post run times, and dwell times are linked. When individual data is entered, dependent data sets are automatically added to the list. In addition, Visum calculates the cumulative delays of individual vehicle journey items. Storing this data in the Visum data model enables a visualization that allows delay hotspots to be identified in the network editor.
The data is transferred without prior checking for consistency. Negative journey or travel times can therefore also be calculated.
Creating an actual timetable from the measured data
The special function Generate vehicle journeys from measured times generates new time profiles and vehicle journeys from the measured information, which are linked to the planned vehicle journeys via a relation. Only time profiles and vehicle journeys based on consistent, measured data with positive run and dwell times are generated.
Comparison and evaluation of actual and target timetables
The simultaneous availability of target and actual timetables allows comprehensive analysis and visualization in all public transport views and procedures in Visum, such as the graphical timetable, the connection analysis, or the schematic line diagram. Line blocking based on the actual timetable determines the costs and vehicle requirements.
