EN 15355:2019

Railway applications - Braking - Distributor valves and distributor-isolating devices

This document applies to distributor valves and distributor-isolating devices.
The distributor valves contained in this document are of graduable release type. Direct release types are not included.
Functionally they are regarded as not containing relay valves of any type, even if the relay valves are physically an integral part of the distributor valves.
This document applies to both distributor-isolating devices mounted separate from the distributor valve and distributor-isolating devices integral with the distributor valve.
This document specifies the requirements for the design, testing and quality assurance of distributor valves and distributor-isolating devices.
The distributor valve and distributor-isolating device are intended to be part of a brake system mounted in a vehicle with maximum length of 31 m and maximum brake pipe volume of 25 l taking into consideration brake pipe inner diameters between 25 mm and 32 mm.

Bahnanwendungen - Bremse - Steuerventile und Bremsabsperreinrichtungen

Dieses Dokument gilt für Steuerventile und Bremsabsperreinrichtungen für Druckluft¬bremsen.
Dieses Dokument gilt für mehrlösige Steuerventile. Einlösige Steuerventile werden nicht behandelt.
Die Funktion des Steuerventils wird ohne Berücksichtigung von Relaisventilfunktionen jeglicher Art betrachtet, auch wenn Relaisventile in das Steuerventil integriert sein können.
Dieses Dokument gilt sowohl für in das Steuerventil integrierte, als auch für separat angeordnete Bremsabsperreinrichtungen.
Dieses Dokument definiert die Anforderungen an Konstruktion, Prüfung und Qualitätssicherung der Steuer¬ventile und Bremsabsperreinrichtungen.
Das Steuerventil und die Bremsabsperreinrichtung werden als Teil eines in einem Fahrzeug eingebauten Bremssystems betrachtet, wobei das Fahrzeug maximal 31 m lang ist, ein maximales Hauptluft¬leitungsvolumen von 25 l aufweist und die Hauptluftleitungsinnendurchmesser zwischen 25 mm und 32 mm liegen.

Applications ferroviaires - Freinage - Distributeurs de freinage et robinet d'isolement

Le présent document s’applique aux distributeurs de frein et aux robinets d’isolement.
Les distributeurs de frein décrits dans le présent document sont de type à desserrage gradué. Les types à desserrage direct ne sont pas couverts.
Sur un plan fonctionnel, ils sont considérés comme ne comportant pas de relais pneumatique d’aucune sorte, même si les relais pneumatiques font partie intégrante des distributeurs de frein.
Le présent document s’applique aux robinets d’isolements montés séparément du distributeur de frein ainsi qu’aux robinets d’isolement intégrés au distributeur de frein.
Il spécifie les exigences à respecter pour la conception, les essais et l’assurance qualité des distributeurs de frein et des robinets d’isolement.
Le distributeur de frein et le robinet d’isolement sont destinés à faire partie d’un système de freinage monté sur un véhicule d’une longueur maximale de 31 m équipé d’une conduite générale d’un volume maximal de 25 l, prenant en compte les diamètres intérieurs de la conduite générale de 25 mm à 32 mm.

Železniške naprave - Zavore - Krmilni ventili in naprave za ločitev krmilnih ventilov od zavornega voda

Ta osnutek evropskega standarda velja za krmilne ventile in naprave za ločitev krmilnih ventilov od zavornega voda.
Krmilni ventili, ki jih vsebuje ta evropski standard, so namenjeni za uporabo pri postopnem zaviranju. Krmilni ventili za neposredno zaviranje niso vključeni.
Funkcionalno se šteje, da ne vsebujejo relejnih ventilov nobenega tipa, tudi če so relejni ventili fizično sestavni del krmilnih ventilov.
Ta evropski standard se uporablja tako za naprave za ločitev krmilnih ventilov od zavornega voda, ki so nameščene ločeno od krmilnega ventila, in za naprave za ločitev krmilnih ventilov od zavornega voda, ki so integrirane s krmilnikom ventila.
Ta evropski standard določa zahteve za projektiranje, preskušanje in zagotavljanje kakovosti krmilnih ventilov in naprav za ločitev krmilnih ventilov od zavornega voda.
Krmilni ventil in naprava za ločitev krmilnih ventilov od zavornega voda sta namenjena kot del zavornega sistema, vgrajenega v vozilo z največjo dolžino 31 m in največjo prostornino zavornega voda 25 l, ob upoštevanju notranjih premerov zavornega voda med 25 mm in 32 mm.

General Information

• Status: Published
• Publication Date: 30-Aug-2019
• Withdrawal Date: 29-Nov-2019
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: CEN/TC 256 - Railway applications
• Drafting Committee: CEN/TC 256/SC 3/WG 47 - Braking
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 15-May-2019
• Due Date: 03-Apr-2019
• Completion Date: 15-May-2019
• Directive: 2008/57/EC - Directive 2008/57/EC of the European Parliament and of the Council of 17 June 2008 on the interoperability of the rail system within the Community (Recast)
• Directive: 2016/797/EU - Directive (EU) 2016/797 of the European Parliament and of the Council of 11 May 2016 on the interoperability of the rail system within the European Union (Text with EEA relevance)
• Mandate: M/483 - Mandate for programming and standardisation addressed to the European standardisation bodies under directive 2008/57/EC in the field of the interoperability of the rail system within the European Union
• Ref Project: SIST EN 15355:2019 - Railway applications - Braking - Distributor valves and distributor-isolating devices

Relations

• Replaces: EN 15355:2008+A1:2010 - Railway applications - Braking - Distributor valves and distributor-isolating devices
• Effective Date: 08-Jun-2022
• Amended By: EN 15355:2019/FprA1 - Railway applications - Braking - Distributor valves and distributor-isolating devices
• Effective Date: 30-Sep-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 15355:2019
01-julij-2019
Nadomešča:
SIST EN 15355:2008+A1:2010

Železniške naprave - Zavore - Krmilni ventili in naprave za ločitev krmilnih ventilov

od zavornega voda

Railway applications - Braking - Distributor valves and distributor-isolating devices

Bahnanwendungen - Bremse - Steuerventile und Bremsabsperreinrichtungen

Applications ferroviaires - Freinage - Distributeurs de frein et robinet d'isolement

Ta slovenski standard je istoveten z: EN 15355:2019
ICS:
45.040 Materiali in deli za železniško Materials and components
tehniko for railway engineering
SIST EN 15355:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 15355:2019
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SIST EN 15355:2019
EN 15355
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2019
EUROPÄISCHE NORM
ICS 45.060.01 Supersedes EN 15355:2008+A1:2010
English Version
Railway applications - Braking - Distributor valves and
distributor-isolating devices

Applications ferroviaires - Freinage - Distributeurs de Bahnanwendungen - Bremse - Steuerventile und

freinage et robinet d'isolement Bremsabsperreinrichtungen
This European Standard was approved by CEN on 18 February 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15355:2019 E

worldwide for CEN national Members.
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SIST EN 15355:2019
EN 15355:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Symbols and abbreviations ...................................................................................................................... 14

4.1 Symbols ............................................................................................................................................................ 14

4.2 Abbreviations ................................................................................................................................................ 14

5 Requirements to function, design and manufacturing ................................................................... 14

5.1 Functional requirements........................................................................................................................... 14

5.2 Control chamber ........................................................................................................................................... 14

5.3 Pilot volume ................................................................................................................................................... 14

5.4 Auxiliary reservoir volume and brake cylinder size ....................................................................... 14

5.5 Shock and vibration .................................................................................................................................... 15

5.6 Service life ....................................................................................................................................................... 15

5.7 Compressed air quality .............................................................................................................................. 15

5.8 Environmental conditions ........................................................................................................................ 15

5.8.1 General ............................................................................................................................................................. 15

5.8.2 Ambient temperature ................................................................................................................................. 15

5.8.3 Altitude ............................................................................................................................................................ 15

5.8.4 Humidity .......................................................................................................................................................... 15

5.8.5 Other environmental specifications ...................................................................................................... 16

5.9 Design requirements regarding structural integrity at maximum pressure ......................... 17

5.10 Tightness ......................................................................................................................................................... 17

5.11 Fire behaviour ............................................................................................................................................... 17

6 Functional requirements and Type tests............................................................................................. 17

6.1 General ............................................................................................................................................................. 17

6.2 Test benches .................................................................................................................................................. 17

6.3 Functional requirements and tests........................................................................................................ 18

6.3.1 General ............................................................................................................................................................. 18

6.3.2 Tightness ......................................................................................................................................................... 18

6.3.3 Inexhaustibility ............................................................................................................................................. 20

6.3.4 Compensation of output pressure during brake application ....................................................... 24

6.3.5 Normal working pressure ......................................................................................................................... 25

6.3.6 Released and stand by position .............................................................................................................. 26

6.3.7 Maximum output pressure in relation to input pressure reduction ......................................... 29

6.3.8 Maximum output pressure and build-up and release times of an individual

distributor valve ........................................................................................................................................... 30

6.3.9 Release time within a train consist ........................................................................................................ 32

6.3.10 Sensitivity ....................................................................................................................................................... 32

6.3.11 Insensitivity .................................................................................................................................................... 33

6.3.12 Control sensitivity and hysteresis .......................................................................................................... 34

6.3.13 Quick service function ................................................................................................................................ 35

6.3.14 Propagation speed ....................................................................................................................................... 36

6.3.15 Inshot function .............................................................................................................................................. 37

6.3.16 Manual release function ............................................................................................................................ 37

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6.3.17 Distributor isolating device ...................................................................................................................... 40

6.3.18 Protection against input pressure overcharge .................................................................................. 45

6.3.19 Initial charging of the brake system of a vehicle ............................................................................... 47

6.3.20 Initial charging of the brake system of a train ................................................................................... 49

6.3.21 Maximum supply pressure ........................................................................................................................ 49

6.3.22 Tests at different temperatures .............................................................................................................. 49

6.3.23 Shock and vibration ..................................................................................................................................... 51

6.3.24 Distributor dump valve .............................................................................................................................. 52

7 In-service assessment ................................................................................................................................. 53

8 Designation ..................................................................................................................................................... 53

9 Identification and marking ....................................................................................................................... 54

9.1 Distributor valve ........................................................................................................................................... 54

9.2 Distributor-isolating device ...................................................................................................................... 54

Annex A (normative) Test benches ..................................................................................................................... 55

A.1 General ............................................................................................................................................................. 55

A.2 Test bench Type A for single vehicle ..................................................................................................... 55

A.3 Test bench Type B for train with 400 m length ................................................................................. 57

A.4 Test bench Type C for train with 500 m length .................................................................................. 57

A.5 Test bench Type D for train with 750 m length ................................................................................. 57

A.6 Test bench Type E for train with 1 200 m length .............................................................................. 57

Annex B (normative) Handle for operating the distributor-isolating device ...................................... 58

Annex C (normative) In-service assessment .................................................................................................... 59

Annex ZA (informative) Relationship between this European Standard and the essential

requirements of EU Directive 2008/57/EC aimed to be covered ............................................... 60

Bibliography ................................................................................................................................................................. 62

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EN 15355:2019 (E)
European foreword

This document (EN 15355:2019) has been prepared by Technical Committee CEN/TC 256 “Railway

applications”, the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by November 2019, and conflicting national standards shall

be withdrawn at the latest by November 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 15355:2008+A1:2010.
The main changes compared to EN 15355:2008+A1:2010 are:
a) the standard’s scope has been modified;
b) normative references have been updated;
c) terms and definitions have been revised;
d) requirements on function, design and manufacturing have been revised;
e) requirements on type tests have been revised;
f) requirements on in-service assessment have been revised;
g) requirements on designation have been revised;
h) requirements on identification and marking have been revised;
i) normative annexes have been revised;
j) Annex ZA has been updated.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association, and supports essential requirements of EU Directive 2008/57/EC.

For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,

Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,

Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,

Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

the United Kingdom.
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EN 15355:2019 (E)
1 Scope
This document applies to distributor valves and distributor-isolating devices.

The distributor valves contained in this document are of graduable release type. Direct release types are

not included.

Functionally they are regarded as not containing relay valves of any type, even if the relay valves are

physically an integral part of the distributor valves.

This document applies to both distributor-isolating devices mounted separate from the distributor valve

and distributor-isolating devices integral with the distributor valve.

This document specifies the requirements for the design, testing and quality assurance of distributor

valves and distributor-isolating devices.

The distributor valve and distributor-isolating device are intended to be part of a brake system mounted

in a vehicle with maximum length of 31 m and maximum brake pipe volume of 25 l taking into

consideration brake pipe inner diameters between 25 mm and 32 mm.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 14198, Railway applications — Braking — Requirements for the brake system of trains hauled by

locomotives
EN 14478:2017, Railway applications — Braking — Generic vocabulary
EN 15611, Railway applications — Braking — Relay valves

EN 45545-2, Railway applications — Fire protection on railway vehicles — Part 2: Requirements for fire

behaviour of materials and components

EN 60721-3-5:1997, Classification of environmental conditions — Part 3: Classification of groups of

environmental parameters and their severities — Section 5: Ground vehicle installations (IEC 60721-3-

5:1997)

EN 61373:2010, Railway applications — Rolling stock equipment — Shock and vibration tests (IEC

61373:2010)
ISO 8573-1:2010, Compressed air — Part 1: Contaminants and purity classes
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 14478, and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/;
• ISO Online browsing platform: available at http://www.iso.org/obp.

NOTE Some of the curves in this clause are simplified, not showing the real pressure development. This is

considered to be sufficient for the purpose of this clause.
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EN 15355:2019 (E)
3.1
distributor valve

apparatus to control a pneumatic output pressure as an inverse function of the variation of the brake pipe

pressure (input pressure)
Note 1 to entry: See Figure 1 and Figure 2.

Note 2 to entry: For the purpose of this European Standard, input pressure is considered to be the brake pipe

pressure and output pressure is usually considered to be the pilot pressure, which controls the brake cylinder

pressure usually via a relay valve.
Key
1 input pressure
2 distributor valve
3 output pressure
Figure 1 — Distributor valve, main function and block diagram
Key
1 normal working pressure level
2 input pressure
3 output pressure
Figure 2 — Distributor valve, main function and pressure diagram
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EN 15355:2019 (E)
3.2
brake application

establishment of a certain output pressure fed by the auxiliary reservoir, initiated by a drop of input

pressure (brake pipe pressure)
Note 1 to entry: See Figure 3.
Key
1 normal working pressure level 4 output pressure
2 input pressure service brake application
3 maximum output pressure emergency brake application
Figure 3 — Service and emergency brake application
3.3
service brake application

establishment of an output pressure less than the possible maximum, initiated by a drop of input pressure

(brake pipe pressure) beginning at the normal working pressure level down to a value between the

minimum reduction and the level of input pressure necessary for full service braking (equivalent to

“service braking” in EN 14478)

Note 1 to entry: This pressure drop causes the distributor valve to establish a corresponding output pressure.

3.4
full service brake application

establishment of the maximum output pressure initiated by a defined drop of input pressure (brake pipe

pressure), beginning from the normal working pressure level down to the specific input pressure level

(equivalent to “full service braking” in EN 14478)
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EN 15355:2019 (E)
3.5
emergency brake application

establishment of the maximum output pressure caused by a drop of input pressure starting with the value

for normal working pressure down to the level necessary for reaching the maximum output pressure in

time t , faster than the specified time for reaching the maximum output pressure, t (equivalent to

1 2
“emergency braking” in EN 14478)

Note 1 to entry: This causes the distributor valve to operate at his maximum capacity, meeting the system

requirements (see Figure 4).

Note 2 to entry: Usually during emergency braking the input pressure is reduced to 0.

Key
1 normal working pressure level
2 input pressure
3 input pressure level necessary for reaching maximum output pressure
4 maximum output pressure
5 output pressure
6 95 % of the maximum output pressure

t time to reach the input pressure necessary to establish maximum output pressure

t time to reach 95 % of the maximum output pressure
Figure 4 —Emergency brake application
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EN 15355:2019 (E)
3.6
brake release

venting the output pressure to atmosphere, initiated by an increase of input pressure (brake pipe

pressure) after a brake application (equivalent to “graduable application and release” in EN 14478)

Note 1 to entry: See Figure 5.
Key
1 normal working pressure level
2 input pressure
3 output pressure
4 1,50 bar below normal working pressure level
Figure 5 — Brake release
3.7
full release

complete venting of output pressure, initiated by an increase of input pressure (brake pipe pressure)

after a brake application up to the normal working pressure level
3.8
graduable application and release

incremental increase/reduction of output pressure initiated by an incremental reduction/increase of

input pressure in the range of pressure from full service braking to full release

3.9
build-up time

time for increasing output pressure from when it starts to rise from 0,00 bar up to 95 % of the maximum

output pressure, when input pressure is reduced from normal working pressure level down to 0,00 bar

with a time of less than 2 s for the first pressure drop of 1,50 bar
3.10
release time

time for reducing the maximum output pressure from the moment when it starts to decrease until it

reaches 0,40 bar, when input pressure is increased up to the normal working pressure level, starting from

1,50 bar below it, in less than 2 s
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EN 15355:2019 (E)
3.11
manual release

function which requires deliberate and intentional manual action in order to cancel brake application (to

release the distributor valve) provided by one distributor valve

Note 1 to entry: Manual release function can be achieved in two ways (see 6.3.16).

3.12
automatic manual release

operation, which requires manual action by the command element after which the release function is

completed automatically
3.13
non-automatic manual release

operation, which requires manual action by the command element during the entire process until the

release function is completed

Note 1 to entry: Stopping action before complete release results in incomplete release.

3.14
stand-by position (ready for operation)

condition of the distributor valve in which braking can be initiated in compliance with all specifications

3.15
normal working pressure
pressure in the brake pipe that corresponds with the brake release condition
[SOURCE: EN 14478:2017, 4.10.4.2]
3.16
sensitivity

ability of the distributor valve to supply an output pressure under certain conditions of input pressure

reduction
Note 1 to entry: See Figure 6.

Note 2 to entry: If a certain value is specified, it gives the minimum gradient of input pressure reduction which

causes the distributor valve to react after a certain time.
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EN 15355:2019 (E)
3.17
insensitivity

ability of the distributor valve to prevent establishing an output pressure under certain conditions of

input pressure reduction

Note 1 to entry: If a certain value is specified, it gives the maximum (fastest) gradient of the input pressure

reduction which will not cause the distributor valve to react.
Key
1 input pressure
distributor valve shall react
2 normal working pressure
3 insensitivity area
distributor valve may react
4 sensitivity area
5 sensitivity limit
distributor valve shall not react
6 insensitivity limit
Figure 6 — Sensitivity and insensitivity areas and limits
3.18
quick service function

function of a distributor valve, when applying the brake from stand-by and released position, which

allows the local fast venting of brake pipe pressure by a certain specified amount and at a certain specified

gradient, to provide pneumatic brake signal transmission through a train
3.19
propagation time

time between the initiation of an emergency brake application by the driver’s brake handle and the

beginning of brake cylinder pressure build-up on the last vehicle of a train
3.20
propagation speed
length of brake pipe divided by propagation time
3.21
normal working pressure overcharge

build-up input pressure above normal working pressure to reduce the release time of a train and/or to

adjust the distributors control chamber pressure of all vehicles of a complete train (equivalent to

“overcharge” in EN 14478)
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EN 15355:2019 (E)
3.22
inshot function

function of the distributor valve which allows a faster increase of the output pressure at the beginning of

brake application (t against t without inshot function)
1 2

Note 1 to entry: The purpose is the quick build-up of the necessary pressure for initiating the friction braking

process, most effective in brake mode G (see Figure 7).
Key
1 maximum output pressure level
2 output pressure
3 pressure necessary for starting the friction process
t with inshot function
t without inshot function

Figure 7 — Inshot function, output pressure development with and without inshot function

3.23
control chamber

air volume connected to, or part of a brake distributor valve, the pressure in which is compared to the

local brake pipe pressure within the distributor valve, and used to determine the distributor valve output

pressure
[SOURCE: EN 14478:2017, 4.10.6.3]
3.24
auxiliary reservoir

container designed to store air under pressure which is protected and dedicated for use by the brakes on

the vehicle to which it is fitted
[SOURCE: EN 14478:2017, 4.10.6.2]
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3.25
pilot volume

volume fed by the output pressure of the distributor valve and used to provide the pilot pressure to the

downstream relay valve
3.26
direct release

function which allows a complete reduction of output pressure in one step initiated by a limited increase

of the brake pipe pressure even if not reaching the normal working pressure
3.27
maximum output pressure

output pressure which is reached after an emergency braking or full service braking

Note 1 to entry: See Figure 3.
3.28
control sensitivity

ability of the distributor valve to respond accurately and sensitively to input pressure modifications by

delivering corresponding output pressure variations
3.29
distributor isolation device
device which isolates the distributor valve from the brake pipe
3.30
normal litre

unit of amount of a gas equal to the amount of 1 l at a pressure of 1,00 bar and at a standard temperature,

at 20 °C
Note 1 to entry: Air flow is often stated in normal litres per minute (Nl/min).
3.31
distributor dump valve

optional valve within or attached to the distributor valve to eliminate an overcharge in the control

chamber as the input pressure of the distributor valve is reduced to 0,00 bar and (optional) increased

again up to service pressure
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EN 15355:2019 (E)
4 Symbols and abbreviations
4.1 Symbols
t time
p pressure
B maximum brake cylinder pressure
CPmax
4.2 Abbreviations
P Brake mode “passenger”
G Brake mode “goods” (freight)
5 Requirements to function, design and manufacturing
5.1 Functional requirements

Functional requirements to be met by the distributor valve and distributor-isolating device are specified

in Clause 6.
5.2 Control chamber

The control chamber may be integral with the distributor valve or as a separate volume.

5.3 Pilot volume

The pilot volume may be integral with the distributor valve, a relay valve or as a separate volume. The

timing chokes of the distributor valve shall be associated with the defined pilot volume. The pressure

inside the pilot volume is the output pressure of the distributor valve. The pilot volume(s) and its

tolerance(s) shall be defined by design documentation.
5.4 Auxiliary reservoir volume and brake cylinder size
Distributor valves for freight wagon
...