Train Activation

An activation message is produced when a train entity is created from a schedule entity by the TRUST system. The train entity refers to a single run of a train on a specific day whereas the schedule entity is potentially valid for several months at a time. Within TRUST, this process is known as Train Call.

Most trains are called automatically (auto-call) before the train is due to run, either 1 or 2 hours depending on the train's class. The TRUST mainframe runs an internal process every 30 seconds throughout the day, causing potentially two lots of train activation messages to be received every minute.

Schedules which is Runs as required, or Runs to terminals/yards as required (flagged with Q or Y in the schedule) are usually called manually - the train operator will submit a message to the TRUST system and this will then cause the schedule to be activated for that day (a process is known as manual call.)

Any train may be manually called some hours in advance if the train is to be cancelled (e.g. a cancellation of a 6pm service which is decided at 8am will result in an auto-call train being manually called and then cancelled).

= Data structure =

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= Linking with Schedule Data =

The train activation message is the only message type which directly links a signalling ID to a schedule. There are ways to infer this relationship using other data, but it is much more difficult.

An individual schedule is identified by the unique schedule identifier (train_uid) and the schedule start date (schedule_start_date). These will identify one or more schedules from the SCHEDULE data feed. If there are several schedules that have the same start date, then the one with the lowest STP indicator character is the valid one. Note: at present, there seems to be a bug in the schedule_type field which does not always match the schedules available in the SCHEDULE feed.

See the how scheduling works page for more details.