| [railML 3] Clarification regarding unused DistanceBasedCalculationRule element [message #4084] |
Mon, 20 July 2026 15:21  |
Ricardo Subtil
Messages: 1
Registered: July 2026
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Junior Member |
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Good afternoon!
While working on import functionality of railML 3.2 timetable schema for our software, I noticed the existence of a DistanceBasedCalculationRule element in the railML 3.2 schema. It looks to be entirely unused, but judging by its semantics, it appears to be a specialization of another rule element for followup sections and calculated reserve times, akin to the existing timeBasedRule.
We would like to use this element as is currently in the schema, since it fits our use-case nicely, without modifications necessary. When communicating calculated reserve times, we need to document the original distance based property for our software to reconstruct the information at import time. Here's an example of how we would use this element in an actual railML export:
<!-- 5 minutes -->
<reserve reserve="PT5M">
<rule>
<!-- 10 minutes every 100 kilometres (100000 metres) -->
<distanceBasedRule referenceDistanceMeters="100000" supplement="PT10M" />
</rule>
</reserve>
The only extension we would require in our software would be to allow this element to be present in the rule element. However we need some clarification if this element should be used as I described. While I believe we have a legitimate use-case for it, it was also subsequently deleted from the upcoming 3.4 version, suggesting a deprecation path.
Kind regards,
Ricardo Subtil
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| Re: [railML 3] Clarification regarding unused DistanceBasedCalculationRule element [message #4088 is a reply to message #4084] |
Thu, 06 August 2026 10:18  |
Christian Rößiger
Messages: 82
Registered: March 2015
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Member |
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Hello Ricardo,
I recall that the railML 3.2 specification was intended to support different rules for runtime reserves. Unfortunately, I cannot explain why, in the end, only one rule made it into the final version, and why this second rule element nevertheless remained in the XSD as a type definition without being used in the schema. As the current modelling of the `rule` element was explicitly designed to allow for extensions, I see no reason why a `distanceBasedRule` could not also be included in a future version of railML.
Ricardo Subtil wrote on Mon, 20 July 2026 15:21
<!-- 5 minutes -->
<reserve reserve="PT5M">
<rule>
<!-- 10 minutes every 100 kilometres (100000 metres) -->
<distanceBasedRule referenceDistanceMeters="100000" supplement="PT10M" />
</rule>
</reserve>
The only extension we would require in our software would be to allow this element to be present in the rule element. However we need some clarification if this element should be used as I described. While I believe we have a legitimate use-case for it, it was also subsequently deleted from the upcoming 3.4 version, suggesting a deprecation path.
I don't know how the rule represented by the 'distanceBaseRule' element actually works, so I'm unable to evaluate if you're using the element in the right way. In particular, it is unclear for me how distances that aren't multiples of 'referenceDistanceMeters' are handled. I would therefore suggest that you specify your rule or send us your own XML/XSD proposal and we introduce a new rule element explicitly for your needs. I'd rather not recycle something when I can't remember what it was originally intended for.
Best regards
Christian Rößiger
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| Re: [railML 3] Clarification regarding unused DistanceBasedCalculationRule element [message #4089 is a reply to message #4088] |
Mon, 10 August 2026 19:35 |
Milan Wölke
Messages: 233
Registered: April 2007
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Senior Member |
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Hi Ricardo,
the reason why the distanceBasedCalculation rule didnt make it into the release was actually, that we didnt know if there was a demand for it. It was not part of any use case we knew about and in consequence we couldnt tell if the element actually was suitable to describe what we want to describe with these rules. The idea is allow importing systems to follow up the logic that lead to the supplement times specified. Basically, exactly like what you wrote. If you say, that this would be useful to you, I can only agree with Christian, please provide us with some description of how you are using it, and what the calculation behind that would be so we can add that to our documentation. I could imagine this to be a late addition for the upcoming 3.4. The reason why the type was removed from 3.4 is simple, we wanted to clean up orphaned types, but of course this could be reversed if there is need for the element.
Assuming that you are want to stay on 3.2, however, this would probably not help you right away. What I would recommend you in this case would be to create an extension of the type RuntimeReserveCalculationRule and add an element of the DistanceBasedCalculationRule type to the choice. If you are unsure, how to do that, please take a look at https://wiki3.railml.org/wiki/Dev:Using_xsi:type.
So in summary, for 3.2, feel free to use the type from the schema in your extension, and for 3.4, we would really appreciate, if you could explain a little on how that calculation is done in your system, so we could add this to the upcoming release.
Best regards, Milan
Milan Hoffmann – Timetable schema coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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