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<railMLv3> Infra Geometry Terminology [message #2021] Fri, 23 November 2018 13:01 Go to next message
Fabrizio Cosso is currently offline  Fabrizio Cosso
Messages: 12
Registered: September 2017
Junior Member
Dear all,
can someone address me to some documents where I can find the exact meaning of terminology used in Geometry View?
e.g. the exact meaning of each curveType, etc...

Thanks

BR

Fabrizio
Re: <railMLv3> Infra Geometry Terminology [message #2024 is a reply to message #2021] Mon, 26 November 2018 16:24 Go to previous messageGo to next message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Fabrizio,

Am 23.11.2018 um 13:01 schrieb Fabrizio Cosso:
> can someone address me to some documents where I can find
> the exact meaning of terminology used in Geometry View?
> e.g. the exact meaning of each curveType, etc...

I suggest to use the UML model documentation (HTML report, available in
[1]) or the XSD schema documentation (HTML, available in [2]). The
railML 3 wiki, where besides the automatically generated schema
documentation detailed definitions, best practices and open issues shall
be adressed, is still under construction.

Regarding your specific question with the curve type:
Generally, railway alignment knows three basic curves:
* straight lines (constant infinite radius)
* arcs (constant radius)
* transition curves (changing radius)
railML introduces in <horizontalCurve>@curveType some more specific
versions of transition curves, e.g. clothoides, cubic parabolas etc.
Some of these curve types are described in more detail e.g. in [3] or [4].

Once, we start with the use case "Track Geometry" [5], we may have a
closer look on these different types.

Best regards
Christian

[1] https://svn.railml.org/railML3/tags/railML-3.1-rc/doc/model
[2] https://svn.railml.org/railML3/tags/railML-3.1-rc/doc/schema
[3]
https://www.brainkart.com/article/Railway-Engineering-Transi tion-Curve_4227/
[4] https://pwayblog.com/2016/07/03/the-clothoid/
[5] https://wiki.railml.org/index.php?title=UC:IS:Track_Geometry

--
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


Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: <railMLv3> Infra Geometry Terminology [message #2153 is a reply to message #2024] Wed, 20 February 2019 17:58 Go to previous messageGo to next message
Adam Hlubuček is currently offline  Adam Hlubuček
Messages: 1
Registered: November 2017
Junior Member
Hello,
in relation to terminology, I would like to ask what does the value "mixed" of rail3:tGradientCurveType mean and when to use it. The semantics seems quite unclear to me. Thank you for your feedback.

Adam Hlubuček
Re: [railML3] Infra Geometry Terminology [message #2160 is a reply to message #2153] Wed, 27 March 2019 07:19 Go to previous messageGo to next message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Adam,

Am 20.02.2019 um 17:58 schrieb Adam Hlubuček:
> in relation to terminology, I would like to ask what does
> the value "mixed" of rail3:tGradientCurveType mean and when
> to use it. The semantics seems quite unclear to me. Thank
> you for your feedback.

sorry for answering so late, but I just recovered from 5 weeks of
illness, so that I missed your posting.

A <gradientCurve> with @curveType="mixed" can be used to model a
gradient curve with an "administrative" gradient value. Imagine the
situation that you have a track from A to B and somewhere on this track
a maximum slope of 25 per mille has to be climbed by the train, but you
don't know exactly, where this gradient appears. In that case, you can
model a <gradientCurve> covering the whole track from A to B with
@gradient="25". By setting @curveType="mixed" it becomes clear, that the
gradient of 25 per mille does not affect the whole track from A to B.

If the community knows further examples where different types of
gradients shall be modelled, please share them here with us in the forum
so that we can discuss them and integrate them in planned Advanced
Example and in the Track Geometry use case.

Thank you very much and 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


Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: [railML3] Infra Geometry Terminology [message #2164 is a reply to message #2160] Mon, 01 April 2019 13:24 Go to previous messageGo to next message
Thomas Nygreen JBD is currently offline  Thomas Nygreen JBD
Messages: 68
Registered: February 2017
Member
Dear all,

The gradient information that we use in Norway can be generalised into two types:

Actual microscopic gradient: only used in an IM perspective (infrastructure models, construction, maintenance, etc.)

Averaged gradient over a certain length: used for operational and signalling purposes. The signalled gradient is a moving average over 1 km. The schematic signal plans show average gradient between signals in the same direction.

Additionally, I would guess that a maximum gradient could also be useful. If so, we should be able to distinguish between types of "mixed" curves, i.e. the aggregation method (average, maximum and maybe more).


Best regards,
Thomas Nygreen
Railway capacity engineer
Jernbanedirektoratet

[Updated on: Mon, 01 April 2019 13:24]

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Re: [railML3] Infra Geometry Terminology [message #2166 is a reply to message #2164] Mon, 08 April 2019 16:52 Go to previous message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Thomas,

Am 01.04.2019 um 13:24 schrieb Thomas Nygreen:
> [...]
> Averaged gradient over a certain length: used for
> operational and signalling purposes. The signalled gradient
> is a moving average over 1 km. The schematic signal plans
> show average gradient between signals in the same
> direction.
>
> Additionally, I would guess that a maximum gradient could
> also be useful. If so, we should be able to distinguish
> between types of "mixed" curves, i.e. the aggregation method
> (average, maximum and maybe more).

thank you for your valuable input from a Norwegian point of view!

From technical side, two possible solutions are possible:
1) extending the value list for <gradientCurve>@curveType replacing the
value "mixed" with new values "maximum" and "average".
2) adding a new attribute <gradientCurve>@aggregationReference with
values "maximum" and "average", which is only set in case of
<gradientCurve>@curveType="mixed".

I prefer solution 1), but the more interesting question for me is if
there are further types of "mixed" gradients apart of maximum and average.

Any feedback is highly appreciated...

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


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