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Dealing with time in VDV 431

“Date” and “DateTime” are processed in different places in VDV 431

Technical description

They are basically processed using times specified in ISO-compliant format. However, on days of operation, the notation DD.MM.YYYY is used. In some cases, times are specified in minutes and in others, in seconds. All responses from VDV 431 are given in Zulu time.

Key concepts

  • Days of operation: Days on which a train is operating.
  • Zulu time: Corresponds to UTC time
  • Hysteresis: With regard to customer information, only amendments which exceed a certain value are forwarded. This happens through hysteresis. This means that delays are not polled, but are forwarded only from a certain amendment. In Switzerland, this is basically 30 seconds as standard.

Technical aspects

The details in Zulu time must be used correctly, depending on the time zone (and summer time). There is no summer time change and therefore, no change in time behaviour in the Zulu time zone. This can give rise to “interesting” route time diagrams for means of transport (trains, buses, trams) which operate when the time changes.

Data structure

The structure complies with ISO 8601.



  • Day of operation: 15.8.2016
  • ISO 8601 2004-06-14T23:34:30
  • Zulu time: 2016-04-02T11:24:00Z-