TT:brakeUsage

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brakeUsage
 


Scheme description / Schemenbeschreibung / Description du schéma

Position of brakeUsage in the XML-Tree / Position von brakeUsage im XML-Baum / position de brakeUsage dans l’aborescence XML

Multiplicity / Anzahl / Multiplicité

[0..1]

Semantics / Bedeutung / Sémantique

The element brakeUsage defines the brake system for the whole train as a "fixed formation".

Attributes of brakeUsage / Attribute von brakeUsage / Attributs de brakeUsage

  • brakeType: This names the type of brake producing the brake effort. According to the way of controlling the brake application one of the following values should be selected:
  • none no brake at all
  • compressedAir (pneumatic) brake system using compressed air to press the brake shoes onto the wheels or brake discs.
    "Druckluftbremse"
  • vacuum brake system using vacuum in the control pipe. The brake shoes are pressed onto the wheels by means of athmospheric air pressure.
    "Saugluftbremse"
  • handBrake manually applied brake by turning a handle or a lever which operates a gear/rod assembly with brake shoes
    "Handbremse"
  • parkingBrake mainly spring applied brake used to keep a parking vehicle stationary
    "Feststellbremse"
  • cableBrake brake applied by a cable running along the train
    "Seilzugbremse", z. B. Bauart Heberlein
  • other:anything Any value that does not fit any value from the previous enumeration list, fulfilling the constraint: at minimum two characters, whitespace is not allowed.
    brake applied by any other mechanism
  • airBrakeApplicationPosition: This is the setting for the air brake application defining the time span for activation. Possible values are:
  • N/A not applicable as brakeType is not compressedAir
  • G slow activation, typical for freight trains or Merchandises
  • P fast activation, typical for passenger trains with speed up to 120 km/h
  • R rapid activation, typical for passenger trains with higher speed
  • regularBrakeMass: This is the brake mass in metrical tons for normal brake operations of none-automatic brakes.
  • emergencyBrakeMass: This is the brake mass in metrical tons for emergency brake operations of none-automatic brakes. It differs from regular brake mass depending on auxiliary brakes.
  • maxDeceleration: This is the alternative specification of maximum possible momentary deceleration in metres per square second. Typically this value is achieved near standstill.
  • meanDeceleration: This is the alternative specification of effective mean deceleration of a whole brake operation in metres per square second.
  • brakePercentage: (deprecated with version 2.2) Defined as the quotient/ratio of the sum of the braking mass of all the vehicles of a formation by the sum of the total mass of all the vehicles of the formation, provided in percent (x 100). The braking mass depends on the selected braking switch (G/P/R) and auxiliary brakes (Mg, H, E, ...) the formation operates with. The total mass depends on the load of the vehicles. Due to these two dependencies, the brakePercentage can only be given for a calculated/scheduled 'instance' of a formation but not for the formation in general.

Due to the usage or not-usage of auxiliary brakes in regular or emergency cases, there are different braking masses and therefore different braking percentages for both cases. Normally, the attributes regularBrakePercentage and emergencyBrakePercentage shall be used. brakePercentage is mainly for backward compatibility. It still can be used if both cases have identical brake percentages. A reading software shall first try to read regularBrakePercentage and/or emergencyBrakePercentage. If the attribute is not existing, it can assume brakePercentage to be identically with the searched value.

  • regularBrakePercentage: This should be used instead of the uncertain brakePercentage as specific value for the regular case.
  • emergencyBrakePercentage: This should be used instead of the uncertain brakePercentage as specific value for the emergency case.
  • xs:anyAttribute: This provides an extension point for non-railML attributes in a foreign namespace. How to use it?

Syntactic Constraints / Syntaktische Beschränkungen / Contraintes syntactiques

  • maxDeceleration: xs:decimal, 3 fraction digits, acceleration value measured in m/s², optional
  • meanDeceleration: xs:decimal, 3 fraction digits, acceleration value measured in m/s², optional
  • brakePercentage: xs:integer, within the range of 6 and 225, brake percentage as value of braking performance in relation to vehicle weight, optional
  • regularBrakePercentage: xs:integer, within the range of 6 and 225, brake percentage as value of braking performance in relation to vehicle weight, optional
  • emergencyBrakePercentage: xs:integer, within the range of 6 and 225, brake percentage as value of braking performance in relation to vehicle weight, optional

If regularBrakePercentage or emergencyBrakePercentage or both are used, brakePercentage is not to be used.

Best practice & Examples / Empfohlene Anwendung & Beispiele / Bonnes pratiques & exemples

It may be assumed that there are defined the following two vehicles at <rollingstock>:
An engine:

<rollingstock  >
  <vehicle id='veh_ME26'  bruttoWeight='122'  >
    <vehicleBrakes>
      <vehicleBrake brakeType='parkingBrake' regularBrakeMass='24'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='G'
			regularBrakeMass='103'
			emergencyBrakeMass='103'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='P'
			regularBrakeMass='129'
			emergencyBrakeMass='129'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularBrakeMass='154'
			emergencyBrakeMass='154'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularBrakeMass='215'
			emergencyBrakeMass='215'>
        <auxiliaryBrakes brakeUse='both' E='true'/>
      <vehicleBrake/>
    </vehicleBrakes>
  </vehicle>
</rollingstock>

And a carriage:

<rollingstock  >
  <vehicle id='veh_DABpza785.2'  bruttoWeight='55.000'  >
    <vehicleBrakes>
      <vehicleBrake brakeType='parkingBrake' regularBrakeMass='5'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='P'
			regularBrakeMass='68'
			emergencyBrakeMass='68'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularBrakeMass='89'
			emergencyBrakeMass='89'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularBrakeMass='95'
			emergencyBrakeMass='95'/>
        <auxiliaryBrakes brakeUse='both' ep='true'/>
      <vehicleBrake brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularBrakeMass='95'
			emergencyBrakeMass='127'>
        <auxiliaryBrakes brakeUse='both' ep='true'/>
        <auxiliaryBrakes brakeUse='emergency' Mg='true'/>
      <vehicleBrake/>
    </vehicleBrakes>
  </vehicle>
</rollingstock>

Example 1

A train consisting of one engine id='veh_ME26' only operating in brake application R+E would look like this:

<timetable >
  <trains>
    <train id='…' type='operational'>
      <trainPartSequence sequence='1'>
        <trainPartRef  >
        <brakeUsage brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			brakePercentage='176'>
          <auxiliaryBrakes E='true'/>
        </brakeUsage>
      </trainPartSequence>
    </train>
</timetable>

brake percentage = 215 t brake mass of that brake application divided by 122 t total mass

Example 2

A train consisting of one engine id='veh_ME26' (operating in brake application R+E ) and four carriages id='veh_DABpza785.2' (operating in brake application R+Mg<ep>) would look like this:

<timetable >
  <trains>
    <train id='…' type='operational'>
      <trainPartSequence sequence='1'>
        <trainPartRef  >
        <brakeUsage brakeType='compressedAir'
			airBrakeApplicationPosition='R'
			regularbrakePercentage='174'
			emergencybrakePercentage='211'>
          <auxiliaryBrakes E='true' Mg='true' ep='true'/>
        </brakeUsage>
      </trainPartSequence>
    </train>
</timetable>

Due to the difference between emergency and regular brake mass of the carriage in brake application R+Mg (the magnetic brake being effective at emergency brake actions only), there is also a difference in the brake percentages of the train.
regular brake percentage = (215+4x95) t divided by (122+4x55) t total mass = 174 %
emergency brake percentage = (215+4x127) t divided by (122+4x55) t total mass = 211 %

Notes / Anmerkungen / Notes

If the brake switch differs in the formation (a part of the formation is switched to a different brake position than the rest of the formation), the value of most of the vehicles is to be given in the attribute airBrakeApplicationPosition as it applies in the General Rules of the Infrastructure Manager. Normally, with long freight trains, the first wagons are set to G and the rest to P, and P is to be published as the train's main air brake position.

Open issues / Offene Punkte/Pedenzen / Questions ouvertes

Not yet described. / Noch nicht beschrieben. / Pas encore décrit.