| Re: Include track length information in topology [message #1813 is a reply to message #1796] |
Wed, 30 May 2018 10:57   |
christian.rahmig
Messages: 436
Registered: January 2016
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Senior Member |
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Dear Martin,
thank you for your extensive conclusion on this discussion. I forwarded
the main question to the RTM developing team [1]. We'll see what happens...
[1] https://www.railml.org/forum/index.php?t=msg&th=579& start=0&
Best regards
Christian
--
Christian Rahmig - Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Phone Coordinator: +49 173 2714509; railML.org: +49 351 47582911
Altplauen 19h; 01187 Dresden; Germany www.railml.org
Am 17.05.2018 um 10:21 schrieb Martin Karlsson:
> The RailTopoModel contains no information about lengths of
> tracks. It is concerned only with the relations between the
> network elements, not with their physical dimensions.
> However, practically all use cases imaginable will need the
> track length information to calculate travel times, to
> compare with train lengths, etc. So in the railML model, it
> has to be included in some way.
>
> This issue has been discussed in a previous forum post
> ( https://www.railml.org/forum/index.php?t=msg&th=472& start=0&),
> and the solution in version 3.1 beta was to introduce a
> Track object within the FunctionalInfrastructure view. The
> Track is mapped to a NetElement in the Topology view, but
> adds a length attribute. A trackside object may be mapped to
> a position at a distance on a Track through the child
> elements trackPosition and trackSection, which were added to
> the RTM originated location elements of spotLocation,
> linearLocation and areaLocation.
>
> It has been argued that this solution adds unnecessary
> complexity to the model, by in effect acting as a second
> layer topology model, within the FunctionalInfrastructure
> view. This could be avoided by instead including length
> information in the Topology view.
>
> A proposal discussed in the In2Rail/railML collaboration
> team is to
> Add an attribute "length" of type tLengthM to the class
> NetElement. NetElement is derived from the RTM class
> LinearElement, which remains unaltered. tLengthM indicates
> that the length is in meters, with decimals. The value of
> "length" shall be the full length between agreed reference
> points in the delimiting crossings, so that the aggregated
> length over consecutive tracks always reflects the correct
> total distance Add an attribute "pos" to the spotLocation
> child element in the Entity class. In order to do this
> without changing the RTM classes SpotLocation and
> LocatedNetEntity, new derived classes may need to be
> created. The value of "pos" shall be the distance from the
> agreed reference point in the crossing at leg 0 of the net
> element In the same way, add attributes "posBegin" and
> "posEnd" of type tLengthM to the associatedElement element
> used in linearLocation and areaLocation child elements of
> the Entity class In the same way, add attributes "posBegin"
> and "posEnd" of type tLengthM to the associatedElement
> element used in linearLocation and areaLocation child
> elements of the Entity class Remove trackPosition and
> trackSection elements from class Entity Remove class Track
> Remove abstract base class TrackNode, and reparent its
> descendants (Switch, Crossing and BufferStop) to Entity. The
> TrackNode was introduced to allow a Track to refer to the
> functional assets at its ends, hence it is no longer needed
>
> The new attributes should all be optional in the XSD, but
> the following application rules should apply:
> "length" shall be mandatory in NetElements within a "Micro"
> description level network (i.e. representing a track),
> optional on other levels "pos", "posBegin" and "posEnd" may
> only be used in Entities referring to a NetElement with a
> "length" When "pos" is defined, "intrinsicCoord" may be
> omitted, as it's value can be derived from "pos" and
> "length" (same rule for posBegin/intrinsicCoordBegin and
> posEnd/intrinsicCoordEnd respectively)
>
>
Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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