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Clearance indication trigger [message #3764] Fri, 24 October 2025 12:59 Go to next message
Terje Nordal is currently offline  Terje Nordal
Messages: 21
Registered: December 2023
Junior Member
Dear all,

As part of engineering of interlocking at Bane NOR, one situation we are required to handle is indicating to a train driver when the back of their train has passed a specific switch clearance. The indication is done either by a trackside lamp (typically in or legacy interlocking systems) or by a notification in the DMI of the train (our ETCS lines). It is often used for stations where long freight trains normally stop, to help them know when they have moved sufficiently long into a track.

In our ETCS engineering we specify this for specific train detectors, in a similar fashion to what we do with route release points (introduced in railML 3.3 as part of #3175). For railML the route release point can be specified as a trigger relating to the <routeExit>. Bane NOR suggest a similar implementation for a "Clearance indication trigger" for railML 3.4.

Best regards
Terje Nordal
Bane NOR

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Re: Clearance indication trigger [message #3781 is a reply to message #3764] Fri, 31 October 2025 16:16 Go to previous messageGo to next message
Jörg von Lingen is currently offline  Jörg von Lingen
Messages: 126
Registered: March 2016
Senior Member
Dear Terje,

the normal route release currently does not include such information in railML. Thus the route exit shall be amended with a reference to such a trigger point.

Is there the need for reference from the route exit to the signal indicator showing the clearance information?

Best regards,
Joerg v. Lingen - Interlocking Coordinator

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Re: Clearance indication trigger [message #3806 is a reply to message #3781] Wed, 03 December 2025 10:01 Go to previous messageGo to next message
Terje Nordal is currently offline  Terje Nordal
Messages: 21
Registered: December 2023
Junior Member
Dear Jörg,

What we model in this use case is a point in the track (typically a train detector) that needs to be passed for the information to be relayed to the train driver (either through DMI information or as a trackside signal (legacy systems)). The function would then affect any train routes passing that detector in a specified direction. That modelling is exactly the same as what we do for route release triggers (introduced in railML 3.3 through https://www.railml.org/forum/index.php?t=msg&th=936& goto=3197&#msg_3197). My understanding was that, in point 2) of that post, the "final route release by train" was related to a release trigger combined with the route exit. A similar implementation for this clearance indication trigger would then make sense.

Our use case does not require a reference from the route exit to the signal indicator showing the clearance information as far as I know. It could, of course, be an optional part, but not something we would model as part of ETCS design at Bane NOR. Our design only mentions the presence of such funtionality,

Best regards
Terje Nordal

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Re: Clearance indication trigger [message #3889 is a reply to message #3806] Mon, 09 February 2026 14:48 Go to previous message
Jörg von Lingen is currently offline  Jörg von Lingen
Messages: 126
Registered: March 2016
Senior Member
An example was already provided by mail.
Adding in <RouteExit> new element <hasClearanceTriggerIndicator>[0..1] with reference to <SignalIndicator>
and <hasClearanceTriggerSection>[0..1] with reference to <TvdSection>

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