Home » railML newsgroups » railML.infrastructure » [railML3] Zero-length tracks (Best practice for describing the location of tracks with 0 length.)
[railML3] Zero-length tracks [message #3516] Tue, 18 March 2025 14:36 Go to next message
David Lichti is currently offline  David Lichti
Messages: 51
Registered: December 2020
Member
Dear Community,

In our railML 3.2 infrastructure export, we came across the case of station tracks that have a length of 0m. This could be the different tracks of block posts, or other purely operational planning locations where trains typically pass without stop.

Is there any recommendation how to model the microscopic topology location of these tracks? Typically, tracks would have a linear location with a start and an end position. But in this case, these positions would coincide. Or should these locations rather be described as a spot location?

Best regards

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Re: [railML3] Zero-length tracks [message #3532 is a reply to message #3516] Fri, 28 March 2025 11:31 Go to previous messageGo to next message
Thomas Langkamm is currently offline  Thomas Langkamm
Messages: 27
Registered: April 2019
Junior Member
I think we should use a spot location. IMO the modelling should always follow the reality whenever possible, and if I understand the use case correctly then you describe a singular spot location here.

I've seen models that used zero-length tracks in the past, and let's just say there were very unfortunate unintended consequences when code tried to handle these zero-length elements.

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Re: [railML3] Zero-length tracks [message #3562 is a reply to message #3532] Mon, 14 April 2025 11:39 Go to previous message
christian.rahmig is currently offline  christian.rahmig
Messages: 510
Registered: January 2016
Senior Member
Dear David and Thomas,

thanks for bringing up this topic.
Having read your postings three times, I still don't understand why you need to model zero-length tracks.

What is the situation:
You have a meso or macro topology with lines (or line sections) and operational points. In addition, you have knowledge about the existence of station tracks and their (usable) lengths, but not about the microscopic topology.

Now, what are the options for locating tracks in that case:
It makes sense to locate the stations tracks with spot locations on the meso/macro (non-linear) netElement of the station. Although they use <spotLocation> elements, the <track> elements can still have a length information.
Alternatively, you can model a micro (linear) netElement for each station track. These netElements are not connected with each other via netRelations, but they are only aggregated by the meso/macro (non-linear) netElement of the station. Then, the station tracks are located with linear locations on the micro (linear) netElements. Also in that case, each <track> element has a length information.

Please let me know if you are missing anything in this approach...

Best regards
Christian

Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org

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