| modelling route proceed speed and approach speed in railML3 [message #3940] |
Tue, 17 March 2026 16:30  |
Torben Brand
Messages: 211
Registered: March 2016
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Senior Member |
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I am a bit uncertain how to model route proceed speed and approach speed in railML3.
Requirements according to RSIM UC [1]
The attributes @proceedSpeed, @approachSpeed and @approachPointRef are implemented on the <route> element in railML2.5 [2] but they are not present on the <route> element in railML3 [3]. I understood it so from the IL coordinator that we should use <aspectRelation> [4] here. The element <aspectRelation> has a @passingSpeed attribute used for proceed speed at the slave signal here on the route entry and refers to an aspect in <has Aspect> [5]
An over-simplified example for proceed speed would be:
<route id="r1"> --- route with proceed speed
<hasAspect genericAspect="limitedProceed" id="a1">
<aspectRelation passingSpeed="80">
<appliestoRoute ref="r-1">
<appliestoRoute ref="r-n">
<slaveAspect>
<showsAspect ref="a1">
As the passingSpeed and slaveAspect refers to the <route/routeEntry> signal you do not need to use <slaveAspect/refersToSignal> so you can list all relevant routes for a generic aspect.
Is this correct?
An over-simplified example for approach speed would be:
<route id="r1"> --- route with approach speed in case of aspect "caution" on distant signal and "closed" on main signal on route entry.
<hasAspect genericAspect="caution" id="a2">
<hasAspect genericAspect="closed" id="a3">
<aspectRelation id="ar1" passingSpeed="130">
<appliestoRoute ref="r-1">
<slaveAspect>
<refersToSignal ref="[distant signal with target approach speed in front of route]">
<showsAspect ref="a3">
<masterAspect>
<refersToSignal ref="[main signal on routeEntry]">
<showsAspect ref="a3">
...
<aspectRelation id="ar-n" passingSpeed="130">
<appliestoRoute ref="r-n">
<slaveAspect>
<refersToSignal ref="[distant signal "n" with target approach speed in front of route]">
<showsAspect ref="a2">
The use of <masterAspect> being optional.
As the approach speed refers to different/individual distant signals for the routes with approach speed you do need to use <slaveAspect/refersToSignal>. Meaning you must refer to each route with approach speed 1:1 with <aspectRelation>.
In case the slaveAspect is a balise (which is possible in Norway for simultaneous entry stations with alternative 2) you need to model the balise also as a virtual distant signal, for <showsAspect> to refer to.
Is this correct?
[1] https://wiki3.railml.org/wiki/UC:IL:RoutesTimetableSimulatio n
[2] https://wiki2.railml.org/wiki/IS:route
[3] https://wiki3.railml.org/wiki/IL:route
[4] https://wiki3.railml.org/wiki/IL:aspectRelation
[5] https://wiki3.railml.org/wiki/IL:hasAspect
[Updated on: Tue, 17 March 2026 16:37] Report message to a moderator |
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| Re: modelling route proceed speed and approach speed in railML3 [message #3944 is a reply to message #3940] |
Sun, 22 March 2026 14:35  |
Jörg von Lingen
Messages: 123
Registered: March 2016
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Senior Member |
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First one have to understand that any distant signal although related to the next main signal is always considered in the route ending at that main signal. Thus it is engineered in the route in rear of the related main signal.
In railML 3.x the dependency of signal aspects, which may represent a speed value, is separated from the route. This is now defined in <aspectRelation> under <signalBox>. One <aspectRelation> can refer to several routes but uses a dedicated start and end, i.e. aspectRelation-route is [1:n] and aspectRelation-signal is [1:1]. In addition to the signal apsects the <aspectRelation> has @passingSpeed for the speed at the route start and @expectingSpeed for the speed at the route end. The element can contain one or more <distantAspect> with reference to the distant signal representing the aspect expected at the route end and marking the normal braking distance in case of a caution aspect.
In the described case in Norway (see attached drawing) the distant signal (DS A221) has a distance to the main signal (MS A221) which is not sufficient for braking to standstill. Therefore a balise is placed in rear of the distant signal to extend the 'visibility' of the distant signal. Then a virtual signal (fDS A221) shall be placed at the location of the balise, which is included in the <aspectRelation> as additional distant signal. In case of caution aspect the balise would mark the start of braking. However, this would result in just one braking curve (red color).
In order to achieve the described case of a two step braking (blue color) from balise to distant signal and from distant signal to target main signal one would need the approach speed at the distant signal. As there is in railML3.3 no attribute in <aspectRelation> to define such approach speed the @approachSpeed of the distant signal element shall be used in such case. This value is normally not needed for distant signals but included for the general description of signals. In railML3.4 attributes for approach speed dependent on aspect at route exit will be introduced for more clarity.
The situation would look in railML as follows
<route id="r1"> --- route from MS A227 to MS A221 with approach speed in case of aspect "caution" on distant signal (DS A221) and "closed" on main signal (MS A221) on route exit.
<signalIL id="sigMSA227" function="block">
<signalIL id="sigfDSA221" function="distant" approachSpeed="200">
<signalIL id="sigDSA221" function="distant" approachSpeed="130">
<signalIL id="sigMSA221" function="entry">
...
<hasAspect genericAspect="proceed" id="a1">
<hasAspect genericAspect="caution" id="a2">
<hasAspect genericAspect="closed" id="a3">
...
<aspectRelation id="ar1" passingSpeed="200" expectedSpeed="0">
<appliestoRoute ref="r1">
<slaveAspect>
<refersToSignal ref="sigMSA227">
<showsAspect ref="a1">
<distantAspect>
<refersToSignal ref="sigfDSA221">
<showsAspect ref="a2">
<distantAspect>
<refersToSignal ref="sigDSA221">
<showsAspect ref="a2">
<masterAspect>
<refersToSignal ref="sigMSA221">
<showsAspect ref="a3">
---
Jörg von Lingen - Interlocking scheme coordinator
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