View source for IS:speedChange


{{ElementDocu|
elementName = speedChange

|parent = {{IS:Tag|speedChanges}}

|childs = {{IS:Tag|additionalName|speedChange}} {{Intro|2.1}}, {{IS:Tag|any}}, {{IS:Tag|geoCoord}}, {{states}}
|minocc=0
|maxocc=∞
|inheritedAttributes =
{{InheritIdName
|id =
|code =
|name =
|description =
}}
{{InheritPosition
|pos =
|absPos =
|absPosOffset =
}}

{{InheritStrictDirection
|selfLink = {{IS:Doc|speedChange}}
|dir =
}}

|ownAttributes =
* {{Attr|trainCategory}} {{depr|2.2}} This is a category name for trains. Use the new attribute '''etcsTrainCategory''' ''(see below)'' instead. Don't confuse with {{TT:Tag|category}}!  
*{{Attr|etcsTrainCategory}}: {{intro|2.2}}{{depr|2.5}} in {{rml|2.2}} to {{rml|2.4}}: the international train category number as specified on page 38 in ERA_ERTMS_040001 "Assignment of values to ETCS variables" v1.9 from 10/07/12. In {{rml|2.5}}: DEPRECATED. Use the new attribute [[IS:speedProfile#etcsTrainCategory|{{attr|etcsTrainCategory}}]] in linked {{tag|IS|speedProfile|attr=etcsTrainCategory}} instead
* {{Attr|profileRef}}: reference to a speedProfile
* {{Attr|status}} defines the status of the speedChange element from perspective of its availability
* {{Attr|vMax}}: maximum allowed speed in km/h (or {{intro|2.3}}: the '''end''' of a restriction){{AddAnn|| }}
* {{Attr|trainRelation}} {{Intro|2.2}} Reference to the part of the train from where the speed change is valid. Normally, a speed change with a speed that is higher than the permitted speed in the section before will be valid only after the end of the train has passed the speed change. On the contrary, a speed change with a speed value that is lower than the permitted speed in the section before applies already when the head of train passes the speedChange. If the attribute is not given, it means that the information is not known. See notes for further information.
* {{Attr|mandatoryStop}}: {{Intro|2.2}} specifying the speedChange as a mandatory stop point, e.g. in front of a level crossing. If the mandatory stop point is physically visualized by a signal/panel, the attribute {{Attr|signalised}} shall be set to true. Further, the related {{IS:Tag|signal}} shall reference the {{IS:Tag|speedChange}}.
* {{Attr|signalised}} {{Intro|2.2}} Indicates whether the speed aspect is shown next to the track by a signal or panel (=true/1) or not (=false/0). For speed changes which are printed in a "Driver's timetable" only but not shown at track-site, use false/0. This is aimed to be used to create special caution for speed changes which are not shown at track-side by special 'highlighting' e. g. in the Driver's timetable. In the meaning of 'on the safe side' this may also apply to speed changes with no proper ''pre''-signalisation (since the pre-signalisation is normally more important than the signalisation at the actual beginning of a speed restriction). A speed change is treated as not pre-signalised if there is at least one route at which a train can pass the speed change decreasing and did not pass any pre-signalisation for the speed reduction a proper braking distance before.
|semcon={{semcon|1=<br>

AS OF 2024-10-02 IS:011 IS DEPRECATED THEREFORE THIS IS A BEST PRACTICE ONLY

*Every {{tag|is|track}} has to have at least one {{tag|is|speedChange}} at the track begin with parameters {{@|pos}}="0" and {{@|dir}}="up".
*Every {{tag|is|track}} has to have at least one {{tag|is|speedChange}} at the track end with parameters {{@|pos}}="{value equal to trackEnd@pos}" and {{@|dir}}="down".
*Only applies if speedChanges are exported at all <ref name="forum">{{site|1=https://www.railml.org/forum/index.php?t=msg&th=905&start=0&|2={{rml|2|link=no}} <speedChange> semantic constraints revision}}</ref>

*It also only applies if both directions can be accessed, otherwise, corresponding exceptions would have to apply.
<br />
Compare {{ticket|425}}

|status=deprecated|proposed=2020-10-12|approved=2021-11-10|deprecated=2024-10-02|forum=https://www.railml.org/forum/index.php?t=msg&th=905&start=0&
|id=IS:011}}
|semantics =
A {{IS:Tag|speedChange}} defines a track element in which position the maximum allowed speed on a track changes. The maximum allowed speed is given in km/h. {{Intro|2.3}}: If the {{IS:Tag|speedChange}} is used to model the end of a temporary speed restriction zone without specifying the ongoing maximum allowed speed, the vMax parameter shall be assigned the value "end". For versions before {{rml|2.3}}, the end of a temporary speed restriction shall be modeled with the "virtual" speed value "999.9".
|notes =
{{InheritPositionNotes}}
===Relationships between overlapping speed changes<br/>{{deu|Beziehungen zwischen sich überlagernden Geschwindigkeitswechseln}}===
All speed changes are to be understood to act independently from each other: A speed change at the front of a train does not affect the speed changes still 'under' the train. The lowest of all speed changes currently valid for a train is relevant. This explains why there is no {{Attr|trainRelation}}="headOfTrainIfDecreasingAndEndOfTrainIfIncreasing" enumeration value. If the speed changes come closer than the length of the train (which may always be the case), the train has to maintain several speed restrictions. If the train passes an increasing speed change (valid for headOfTrain) with its front but has not yet passed a lower increasing speed change (valid for endOfTrain) with its end, the lower speed still has to be maintained - ''in spite of'' the new speed change being valid for head of train. But anyway, the train has also to remember the new speed, so it cannot ignore the new speed change.
 
This is only another (but less obvious) variant of the very common case where a train is in one speed restriction with it’s end and already in a next speed restriction with it’s front, so never enjoying the raised speed between both restrictions - a case which all drivers of the world must handle.

===Usage of {{Attr|vMax}}='end' and {{Attr|dir}}===
Speed changes are always understood directional. This means that a speed change that is specified without providing the attribute {{Attr|dir}} cannot be interpreted and shall be ignored. The direction is also important when specifying speed changes that are terminated by a speed change with the attribute {{Attr|vMax}} set to the value 'end'. If the speed applies to the nominal direction of the enclosing {{IS:Tag|track}}, it is expected to specify the terminating {{IS:Tag|speedChange}} with a higher {{Attr|pos}} value than the corresponding initiating {{IS:Tag|speedChange}}. When describing a speed change that is terminated as such in reverse direction of the enclosing {{IS:Tag|track}} the terminating {{IS:Tag|speedChange}} (the one with {{Attr|vMax}} = 'end') is expected to have a lower {{Attr|pos}} value.<br>
It is also important to note that a terminating {{IS:Tag|speedChange}} always relates to initiating speed changes that refer to the same {{IS:Tag|speedProfile}}. In case a terminating {{IS:Tag|speedChange}} does not refer to any {{IS:Tag|speedProfile}}, it terminates '''ALL''' previous speed changes (with respect to the {{Attr|dir}} attribute). 

===Mandatory braking {{deu|Betriebsbremsung}}===
In {{rml}} {{ticket|227}} the implementation of a "mandatory braking" attribute has been discussed. In the end it was decided not to add a new parameter to {{IS:Tag|speedChange}}, because the final speed after braking is not specified. Users looking for a way to model mandatory braking sections for the beginning should think of choosing a user-specific extension under {{IS:Tag|trackElements}} and come up with new suggestions for {{rml|3}} if needed.
 
|constraints =
{{semconHint}}
{{InheritIdNameConstraints}}
{{InheritPositionConstraints}}
* {{Attr|dir}}: {{railMLType|tStrictDirection}}; optional
*{{constraint|trainCategory|xsd|string}}
*{{constraint|etcsTrainCategory|xsd|integer}}
*{{constraint|profileRef|rml|tGenericRef}}
*{{constraint|status|xsd|string}}
*{{constraint|vMax|rml|tSpeedKmPerHour|required}}<br>
: {{Intro|2.3}}: union of tSpeedKmPerHour and the enumeration value of "end"
*{{constraint|trainRelation|rml|tTrainRelation}}; enumeration: "headOfTrain" / "midOfTrain" / "endOfTrain"
*{{constraint|mandatoryStop|xsd|boolean}}
*{{constraint|signalised|xsd|boolean}}
|backHome = IS:elements
|example=

*Every {{tag|is|track}} has to have at least one {{tag|is|speedChange}} at the track begin with parameters {{@|pos}}="0" and {{@|dir}}="up".
*Every {{tag|is|track}} has to have at least one {{tag|is|speedChange}} at the track end with parameters {{@|pos}}="{value equal to trackEnd@pos}" and {{@|dir}}="down".
*Only applies if speedChanges are exported at all <ref name="forum">{{site|1=https://www.railml.org/forum/index.php?t=msg&th=905&start=0&|2={{rml|2|link=no}} <speedChange> semantic constraints revision}}</ref>

*It also only applies if both directions can be accessed, otherwise, corresponding exceptions would have to apply.
<br />
Compare {{ticket|425}}

Consider {{rml|2.3}} example of {{site|1=https://www.railml.org/en/user/exampledata.html?file=files/download/exampledata/090318_Bahnkonzept_ExampleDataGPSinfradat_NorthUpperRhineNetworkRailML23.zip|2=Middle Rhine Railway by GPSinfradat}}.

This code example defines {{tag|IS|speedChange}} of track adjacent to Bft Bingen (Rhein) Vorbahnhof station.
<syntaxhighlight lang=xml>
<speedChanges>
  <speedChange id="sc2630i0" dir="up" pos="0" vMax="0" absPos="91104" xml:lang="en" description="The value &quot;0&quot; has been set because the maximum permitted speed at the beginning of the route is unknown." trainRelation="headOfTrain"/>
  <speedChange id="sc26300" dir="up" pos="582" vMax="140" absPos="91632" signalised="true" trainRelation="headOfTrain"/>
  <speedChange id="sc26301" dir="up" pos="15613" vMax="110" absPos="106663" signalised="true" trainRelation="headOfTrain"/>
…
</speedChanges>
</syntaxhighlight>
Consider {{rml|2.2}} example of {{site|1=https://www.railml.org/en/user/exampledata.html?file=files/download/exampledata/130416_iRFP_ExampleDataFBS_EastSaxonyRailML.zip|2=East Saxony railway network by FBS}}.

This code example defines {{tag|IS|speedChange}} of track located between Arnsdorf West and Arnsdorf Nord junctions.
<syntaxhighlight lang=xml>
<speedChanges>
  <speedChange id='spc_80.6228u1_0' pos='0' absPos='942' dir='up' profileRef='spp_0' vMax='100'/>
  <speedChange id='spc_80.6228d2_942' pos='942' absPos='23982' dir='down' profileRef='spp_1' vMax='100'/>
  <speedChange id='spc_80.6228u3_0' description='R500' pos='0' absPos='942' dir='up' profileRef='spp_2' vMax='100'/>
  <speedChange id='spc_80.6228u3_112' pos='112' absPos='830' dir='up' profileRef='spp_2' vMax='110'/>
  <speedChange id='spc_80.6228d4_942' pos='942' absPos='23982' dir='down' profileRef='spp_2' vMax='100'/>
</speedChanges>
</syntaxhighlight>

== References ==
<references /> 

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