prEN 13232-3 rev
(Main)Railway applications - Track - Switches and crossings for Vignole rails - Part 3: Requirements for wheel/rail interaction
Railway applications - Track - Switches and crossings for Vignole rails - Part 3: Requirements for wheel/rail interaction
This part of this European Standard defines the main wheel/track interaction criteria to be taken into account during the geometrical design of switches and crossings (S&C) layouts.
It specifies:
- characterisation of wheel and track dimensions;
- geometric design principles for wheel guidance;
- design principles for wheel load transfer;
- deciding whether movable crossings are needed.
These are illustrated by their application to turnout components:
- switches;
- crossings;
- check rails,
but the principles apply equally to more complex layouts. There are also simplified definitions of the safety and functional dimensions, which can be used in conjunction with the general principles as the basis for more in-depth assessment.
Bahnanwendungen - Oberbau - Weichen und Kreizungen für Vignolschienen - Teil 3: Anforderungen an das Zusammenspiel Rad/Schiene
Der vorliegende Teil dieser Europäischen Norm legt die Hauptkriterien des Zusammenspiels Rad/Schiene fest, die während der Phase des geometrischen Entwurfs von Gleisanlagen mit Weichen und Kreuzungen zu berücksichtigen sind.
Er legt Folgendes fest:
- die Beschreibung der Rad- und Gleisabmessungen;
- die geometrischen Entwurfsgrundsätze für die Radführung;
- Entwurfsgrundsätze für die Radlastübertragung;
- die Entscheidung darüber, ob Herzstücke mit beweglichen Bauteilen erforderlich sind.
Diese werden entsprechend ihrer Anwendung auf die Weichenbauteile
- Zungenvorrichtungen;
- Herzstücke;
- Radlenker;
dargestellt, jedoch sind die Grundsätze gleichermaßen auch auf umfangreichere Gleisanlagen anwendbar. Es gibt auch vereinfachte Definitionen der Sicherheits- und Funktionsmaße, die in Verbindung mit den allgemeinen Grundsätzen als Grundlage für eine tiefergehende Bewertung angewendet werden können.
Applications ferroviaires - Voie - Appareils de voie - Partie 3: Exigences pour l'interaction Roue/Rail
La présente partie de la Norme Européenne définit les principaux critères d'interaction entre les roues et la voie à prendre en compte pendant la conception géométriques des types d'appareils de voie.
Elle spécifie :
- la caractérisation des dimensions des roues et des voies ;
- le principe de conception géométrique pour le guidage des roues ;
- les principes de conception pour le transfert de charge des roues ;
- la décision sur la nécessité d’utiliser des cœurs à parties mobiles.
Les sujets sont illustrés par l'application aux composants du branchement :
- aiguillages ;
- cœurs ;
- contre-rails,
mais les principes s'appliquent également aux appareils de voie plus complexes. Il existe également des définitions simplifiées des dimensions sécuritaires et fonctionnelles, qui peuvent être utilisées conjointement avec les principes généraux comme base d'une évaluation plus approfondie.
Železniške naprave - Zgornji ustroj proge - Kretnice in križišča za Vignolove tirnice - 3. del: Zahteve za stik kolo-tirnica
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2014
äHOH]QLãNHQDSUDYH=JRUQMLXVWURMSURJH.UHWQLFHLQNULåLãþD]D9LJQRORYHWLUQLFH
GHO =DKWHYH]DVWLNNRORWLUQLFD
Railway applications - Track - Switches and crossings for Vignole rails - Part 3:
Requirements for wheel/rail interaction
Bahnanwendungen - Oberbau - Weichen und Kreizungen für Vignolschienen - Teil 3:
Anforderungen an das Zusammenspiel Rad/Schiene
Applications ferroviaires - Voie - Appareils de voie - Partie 3: Exigences pour l'interaction
Roue/Rail
Ta slovenski standard je istoveten z: prEN 13232-3 rev
ICS:
45.080 7UDþQLFHLQåHOH]QLãNLGHOL Rails and railway
components
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2014
ICS 93.100 Will supersede EN 13232-3:2003+A1:2011
English Version
Railway applications - Track - Switches and crossings for
Vignole rails - Part 3: Requirements for wheel/rail interaction
Applications ferroviaires - Voie - Appareils de voie - Partie Bahnanwendungen - Oberbau - Weichen und Kreizungen
3: Exigences pour l'interaction Roue/Rail für Vignolschienen - Teil 3: Anforderungen an das
Zusammenspiel Rad/Schiene
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 256.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 13232-3 rev:2014 E
worldwide for CEN national Members.
prEN 13232-3:2014 (E)
Contents
Page
Foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Inputs . 9
4.1 General . 9
4.2 Wheel and track parameters . 9
4.2.1 Wheel profiles . 9
4.2.2 Wheelsets . 10
4.2.3 Rail and track . 10
4.2.4 Tolerances and wear . 11
4.3 Contact zone . 12
4.3.1 Contact profile . 12
4.3.2 Contact danger zone . 12
4.3.3 Flangeway depth. 12
4.3.4 Flangeway width . 13
5 Guidance principles . 13
5.1 Guard and check rails . 13
5.2 Wheelset guidance . 13
5.2.1 Angle of attack . 14
5.2.2 Flangeway . 14
5.2.3 Gauge widening . 15
5.2.4 Check rail and common crossing nose . 15
5.2.5 Obtuse Crossings . 15
5.3 Transitional guidance . 17
5.4 Entry flares . 17
6 Rules . 17
6.1 Introduction . 17
6.2 Security against derailment . 17
6.3 Wheel profiles and wear . 18
6.4 Angle of attack . 19
6.5 Apparent wheel profiles . 20
6.6 Tangent and secant contact . 21
7 Common derailment-critical situations . 21
7.1 Tangent contact . 21
7.2 Secant contact at partially open switch tip or crossing nose . 22
7.3 Secant contact at damaged switch tip (for information only) . 24
7.4 Limits . 25
8 Output - Functional and Safety Dimensions (FSD) . 25
8.1 Switch panel . 25
8.1.1 Free wheel passage in switches F . 25
WPS
8.1.2 Entry angle . 26
8.1.3 Switch point relief A2 . 27
8.1.4 Lateral point retraction . 29
8.1.5 Lateral point machining . 30
8.1.6 Gauge in diverging track – vehicle with 3 axles inscription . 31
8.2 Closure panel . 32
prEN 13232-3:2014 (E)
8.3 Common crossing panel . 32
8.3.1 Fixed nose protection N . 32
pcf
8.3.2 Free wheel passage F . 33
wpcf
8.3.3 Free wheel passage at check rail entry F . 33
wpcre
8.3.4 Free wheel passage at wing rail entry F . 34
wpwre
8.3.5 Minimum flangeway depth h . 36
fw
8.3.6 Flangeway width in diverging track . 36
8.3.7 Parallel check rail length . 38
8.3.8 Check rail and raised check rail . 38
8.4 Obtuse crossing panel . 38
8.4.1 Free wheel passage F . 38
wpof
8.4.2 Unguided length . 41
8.4.3 Check rail and raised check rail . 41
8.4.4 Free wheel passage at check rail entry . 41
8.4.5 Nose protection N . 42
pof
8.5 General items (may occur in all zones within or outside S&C) . 44
8.5.1 Check rail and wing rail entry flare . 44
8.5.2 Flangeway width – Wheel trapping . 44
9 Additional requirements . 44
9.1 Guidance . 44
9.2 Load transfer . 44
9.3 Insufficient wheel support or guidance. 44
9.4 Wheel load transfer . 44
9.4.1 Sufficiency of bearing area . 46
9.4.2 Transfer surfaces . 47
9.4.3 Method of assessment . 47
9.5 Insufficient wheel support or guidance. 47
9.5.1 Common crossings . 47
9.5.2 Obtuse crossings . 48
9.5.3 Movable crossings . 48
Annex A (informative) Functional and safety dimensions, practically used by different
European Networks . 49
Annex B (normative) Maximum angle of attack in obtuse crossings . 50
Annex C (informative) Example of Entry Flare Rule . 52
Bibliography . 53
prEN 13232-3:2014 (E)
Foreword
This document (prEN 13232-3:2014) has been prepared by Technical Committee CEN/TC 256
“Railway applications”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 13232-3:2003+A1:2011.
This series of standards “Railway applications – Track – Switches and crossings for Vignole rails”
covers the design and quality of switches and crossings in flat bottomed rail. The list of Parts is as
follows:
Part 1: Definitions
Part 2: Requirements for geometric design
Part 3: Requirements for wheel/rail interaction
Part 4: Actuation, locking and detection
Part 5: Switches
Part 6: Fixed common and obtuse crossings
Part 7: Crossings with moveable parts
Part 8: Expansion devices
Part 9 : Layouts
Part 1 contains terminology used throughout all parts of this series. Parts 2 to 4 contain basic design
guides and are applicable to all switch and crossing assemblies. Parts 5 to 8 deal with particular
types of equipment including their tolerances. These use Parts 1 to 4 as a basis. Part 9 defines the
functional and geometric dimensions and tolerances for layout assembly.
The following terms are used within to define the parties involved in using the EN as the technical
basis for a transaction:
Customer the Operator or User of the equipment, or the Purchaser of the equipment on the User's
behalf.
Supplier the Body responsible for the use of the EN in response to the Customer's requirements.
prEN 13232-3:2014 (E)
1 Scope
This part of this European Standard defines the main wheel/track interaction criteria to be taken into
account during the geometrical design of switches and crossings (S&C) layouts.
It specifies:
characterisation of wheel and track dimensions;
geometric design principles for wheel guidance;
design principles for wheel load transfer;
deciding whether movable crossings are needed.
These are illustrated by their application to turnout components:
switches;
crossings;
check rails,
but the principles apply equally to more complex layouts. There are also simplified definitions of the
safety and functional dimensions, which can be used in conjunction with the general principles as the
basis for more in-depth assessment.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
prEN 13232-1:2013, Railway applications – Track – Switches and crossings for Vignole rails – Part 1:
Definitions
prEN 13232-4:2014, Railway applications – Track – Switches and crossings for Vignole rails – Part 4:
Actuation, locking and detection
prEN 13232-5:2014, Railway applications – Track – Switches and crossings for Vignole rails – Part 5:
Switches
EN 13803-2, Railway applications – Track – Track alignment design parameters – Track gauges
1435 mm and wider – Part 2: Switches and crossings and comparable alignment design situations
with abrupt changes of curvature
EN 13715, Railway applications – Wheelsets and bogies – Wheels – Tread profile
UIC 505-1, Railway transport stock – Rolling stock construction gauge
UIC 505-4, Effects of the application of the kinematic gauges defined in the 505 series of leaflets on
the positioning of structures in relation to the tracks and of the tracks in relation to each other
UIC 510-2, Trailing stock – Conditions concerning the use of wheels of various diameters with
running gear of different types
prEN 13232-3:2014 (E)
3 Terms and definitions
3.1
guiding force Y
force, acting parallel to the running surface, between the wheel and the relevant track component
(usually a rail)
3.2
wheel load Q
force, acting perpendicular to the running surface, between the wheel on one hand and the relevant
track component (rail)
3.3
contact angle γ
A
angle of the contact plane, measured at the contact point A between the wheel and the track
component. In the case of a two-point contact, the one nearest the wheel flange shall be considered.
See Figure 1.
Key
γ contact angle
A
A contact point
Figure 1 — Contact angle
This contact angle determines the contact danger zone on the wheel, as defined in Figure 5.
3.4
friction coefficient µ
friction coefficient encountered at the contact point where the contact angle is determined
prEN 13232-3:2014 (E)
3.5
flange sharpness q
R
parameter which characterises the sharpness of the wheel flange. The measurement is taken in
accordance with UIC 510-2 at the active side of the flange as defined in Figure 2. It is the distance,
parallel to the wheel axis, between the following two points:
• reference point on the profile, at a distance from wheel axis of 10 mm more than the wheel
radius;
• a reference point, located at a distance 2 mm from the flange tip towards the wheel axis.
Key
a wheel back to back q flange sharpness
R
b flange width R wheel radius
h flange depth
fl
Figure 2 — Wheel parameters
3.6
flange depth h
fl
see Figures 2 and 5
3.7
wheel back-to-back a
see Figures 2, 5 and 31. The symbol “a” is used throughout this standard. An index max or min is
given to this symbol according respectively to the maximum and minimum values that can occur
during operation
3.8
flange width b
see Figures 2 and 5. The symbol "b" is used throughout this standard. An index max or min is given
to this symbol according respectively to the maximum and minimum values that can occur during
operation
3.9
switch point retraction E
distance, measured at the reference plane, between the reference line of switch and stock rail at the
actual switch toe
prEN 13232-3:2014 (E)
Key
E Point retraction
Z1 Switch rail machining reference plane (see prEN 13232-5:2014)
Z2 Stock rail machining reference plane (see prEN 13232-5:2014)
Figure 3 — Switch point retraction
3.10
point retraction in fixed common crossing
reference line in a fixed common crossing which can deviate from the theoretical geometry line. From
a certain distance to the crossing point, the reference line of the Vee can, depending on the design,
be removed from this theoretical line away from the wheel flange in order to avoid contact between
both elements. This situation is described in Figure 4
Key
1 Theoretical reference line
2 Actual reference line
3 Point retraction
4 Mathematical point (MP)
5 Actual point (RP)
Figure 4 — Point retraction in fixed common crossing
prEN 13232-3:2014 (E)
The value of the point retraction is measured at the actual point (RP).
4 Inputs
4.1 General
The motion of wheels and transfer of wheel loads is a complex subject, involving the accumulation of
extensive data and an understanding of dynamic effects.
By making certain assumptions it is feasible to define rules which are simple yet rigorous enough for
design of all types of switches and crossings. Some of these rules assume a 2-axle bogie or vehicle.
The need for other special requirements such as those posed by 3-axle or other vehicles must be
stated by the Customer.
4.2 Wheel and track parameters
This clause deals with the key parameters needed for the analysis of the interaction between wheels
and the track, either for guidance calculations or load transfer calculations.
Wheel and track dimensions are defined below.
4.2.1 Wheel profiles
Sufficient dimensions of the cross-section or profile of a wheel are required for switch and crossing
design. As a minimum, a dimensioned profile drawing shall be provided by the customer, with the
following key dimensions as defined in Figure 5:
flange width, height and flange angle;
tyre width and tread angle;
wheel diameter or radius.
prEN 13232-3:2014 (E)
Key
1 Tyre width 6 Danger zone
2 Flange angle 7 Contact point
3 Flange width 8 Wheel diameter
4 Wheel back to back 9 Tread angle
5 Flange depth
Figure 5 — Key wheel dimensions (in addition to profile details)
4.2.2 Wheelsets
Additional parameters related to the wheelsets are required for calculations for wheelset guidance.
The Customer shall provide the following parameter values:
wheel back-to-back (see Figure 2 or 5);
axle spacing;
number of axles;
clearance of middle axles, if applicable;
bogie spacing and minimum curve radius for vehicles.
4.2.3 Rail and track
The key parameters related to the track geometry which are used in calculations for wheelset
guidance are shown in Figure 6 and listed below:
centreline radius (R);
track gauge (G);
dimension for nose protection (check gauge) (F);
wing flangeway (D).
prEN 13232-3:2014 (E)
Key
1 Highside
2 Wing
3 Check
4 Lowside
Figure 6 — Key track dimensions
and the following shall be provided by the Customer:
maximum permissible check rail height above running table (H).
4.2.4 Tolerances and wear
It is necessary to consider tolerances and wear in order to design correctly. These are alternatively
referred to as manufacturing tolerances and service tolerances.
If the Customer provides worn wheel profiles or amounts of wear, then these should be used.
Otherwise the assumptions made by the Supplier shall form the basis for design, and these shall be
stated. Examples of key areas of wear are:
back of wheel flanges;
front of wheel flanges;
false flanges;
flange angle.
prEN 13232-3:2014 (E)
Locations of typical lateral wheel and track wear are shown in Figure 7. These must be taken into
account when designing flangeway gaps. See clause 5.
Key
1 False flange 4 Wing wear
2 Guard or check rail wear 5 Wheel wear (front)
3 Wheel wear (back) 6 Vee wear
Figure 7 — Locations of wheel and rail wear
Vertical wear, examples of which are also illustrated in Figure 7, is more relevant to wheel load
transfer. See clause 6.
False flanges are to be avoided as they will increase wear as well as the rate of damage to switches
and crossings.
4.3 Contact zone
For switch and crossing design, there are issues which shall be verified during design. These are as
follows.
4.3.1 Contact profile
The relative radii of wheel and rail shall be taken into account.
4.3.2 Contact danger zone
The wheel profile supplied by the Customer shall indicate the danger zone for guidance contact,
which is that part of the wheel flange which falls on the flange radius and which therefore exceeds the
angle for safe guidance. The switch and crossing Supplier shall ensure that guidance contact does
not take place within this zone for both new and worn wheels, except where it is agreed that flange-
running is a normal operating regime.
The danger zone is illustrated in Figure 1 and 5.
4.3.3 Flangeway depth
The depth of the flangeway shall be sufficient to prevent flanges from running on the floor of the
flangeway except if otherwise required by the Customer. This shall be verified considering the
increased depth of flange of a maximum worn wheel and with the shallow flangeway of a maximum
worn running surface of a rail.
prEN 13232-3:2014 (E)
4.3.4 Flangeway width
Flangeway width is governed by a number of vehicle and track parameters as described in the
following sections.
5 Guidance principles
The guidance of a wheelset through switches and crossings concerns mainly the lateral or horizontal
dimensions of wheel, axle, and track. Note that, in Figures 9, 10, 11 and 12, the wheels are shown in
a simplified form as ellipses at the gauge reference plane.
5.1 Guard and check rails
Guard and check rails are rails which bear on the face of the wheel (usually the back face) to provide
guidance without load bearing.
Figure 8a) — Check rail (normally active)
Figure 8b) — Guard rail (normally passive)
Figure 8 — Active v passive guarding
Operation of guard and check rails depends on whether they are intended to be passive or active.
Passive guard rails come into operation after incipient derailment and are intended to rerail wheels
once they have begun to climb the opposite running rail.
Active check rails are intended to make contact with the back of the wheel flange under normal
conditions of operation in order to protect the opposite running rail. See Figure 8.
5.2 Wheelset guidance
In order to determine wheelset guidance, it is necessary to make an assumption of the way in which
the wheelset is constrained to move. The assumption is shown in Figure 9. When the wheelset, bogie
or vehicle is superimposed upon the track, it moves along a trajectory which is skewed relative to the
track running edges.
prEN 13232-3:2014 (E)
Figure 9a) Unchecked Figure 9b) Checked
Key
1 Highside 5 Leading axle
2 Lowside 6 Clearance
3 Angle of attack 7 Check
4 Trailing axle 8 Wing
Figure 9 — Wheelset trajectory
Given the assumption of the mode of running and the resulting angle of attack, it is possible to
determine the adequacy of the flangeway, the effectiveness of protection to the crossing nose, and
the support for wheel load transfer.
The assumed trajectory provides for the worst case, or the maximum possible angle of attack, and
subjects the leading wheel to the closest contact with a crossing nose, and subjects the trailing wheel
to the poorest load transfer.
5.2.1 Angle of attack
The greatest angle of attack is achieved when the wheelset is running around a curve. For curves
without check rails, the bogie will travel as in Figure 9a, with the high-side wheel of the leading axle in
contact with the running edge of the high-side rail and the low-side wheel of the trailing axle in
contact with the running edge of the low-side rail.
The angle of attack is usually reduced if the bogie is constrained as in Figure 9b. The leading axle
runs with the low-side inner wheel flange against the check rail, and the low-side wheel of the trailing
axle is in contact with the running edge of the low-side running rail.
5.2.2 Flangeway
The flangeway shall be wide enough to allow the flanges of the wheels to pass without being trapped
or being forced to climb and derail. See Figure 10 which illustrates wheel trapping.
prEN 13232-3:2014 (E)
Key
1 Highside
Figure 10 — Minimum flangeway (for wheel trapping)
5.2.3 Gauge widening
Gauge widening may be applied to the lowside rail to prevent trapping of the wheels of a bogie. Refer
to Figure 11 which illustrates bogie trapping.
Key
1 Leading axle
2 Trailing axle
3 Highside
4 Lowside
Figure 11 — Minimum gauge (for bogie trapping)
The extent and amount of gauge widening shall be defined by the Customer or calculated by the
Supplier based on sufficient details of the Customer's rolling stock.
5.2.4 Check rail and common crossing nose
A minimum parallel length of check rail shall be provided opposite the fixed crossing nose to protect
the otherwise unguided zone of the crossing, which consists of the throat flare, crossing gap and side
planing. If the parallel length is less than this minimum, it shall be agreed with the Customer.
5.2.5 Obtuse Crossings
A crossing gap L exists between one nose (end of the vee) of the crossing and the knuckle (smallest
gap between the wing and the check rail) as shown in Figure 12. Where obtuse crossings are used in
pairs such as in diamond crossings or slips, it is necessary to verify the extent of guidance.
prEN 13232-3:2014 (E)
X Centreline to Nose – guidance re-established X Unguided distance
X
Centreline to Knuckle where guidance is broken F Dimension for nose protection
Key
1 Level of II
2 Level of I
3 Wheel
4 Direction
5 Crossing gap L
6 Wheel axis
Figure 12 — Diamond crossing – Wheel trajectory
prEN 13232-3:2014 (E)
Figure 12 shows how a wheelset passes through an obtuse crossing. The value of X is the unguided
distance. In the special case of an obtuse crossing a positive value of X, which represents a partly
unguided trajectory, is permitted. However the value of X shall, if positive, be agreed between the
Customer and the Supplier.
5.3 Transitional guidance
Where there are both unchecked track and checked track sections together there will be zones of
transitional guidance in between. To date, however, there is no precise or widespread rule for the
choice of flare to be used to gain control of a wheel passing from unchecked to checked track.
Therefore if the Customer has established rules and parameter values then they shall be provided to
the Supplier, or the two parties must agree the parameter values.
5.4 Entry flares
The entry flare is the part of the check or guard rail or wing in which the flangeway gap width varies
towards the end of the check, guard rail or wing.
A low value of the entry flare, which determines a long check rail, produces perturbations for a longer
time than those observed under the same conditions for a shorter check rail with high value for entry
flare.
On the other hand, transverse forces increase with the high values of entry flare, but the energy (as
the integration of transverse force with distance) is lower for high entry flares than for lower ones.
The entry flare angle shall therefore be agreed between Customer and Supplier. See also Annex C.
6 Rules
6.1 Introduction
The general rules are clarified as follows:
• First, the general law for derailment calculations is described. This law is to be used for safety
calculations.
• Secondly, a list of commonly appearing dangerous situations is given. These situations can
appear during operation and are influenced by maintenance conditions and/or design options.
• From these considerations, functional and safety dimensions are determined later in this
standard.
6.2 Security against derailment
Security against derailment is considered to be guaranteed by limiting the ratio of guiding force Y to
actual wheel load Q. Y and Q are to be determined simultaneously. The limiting value depends on the
friction coefficient µ and contact angle γ .
A
This relation is given by formula (1) or (2).
Y tan(γ ) − µ
A
=
Q 1+ µ.tan(γ )
A
(1)
or, in another form :
prEN 13232-3:2014 (E)
Y
( )
γ = arctan +arctan µ
A
Q
(2)
From this law an admissible contact angle is given, by determining an acceptable Y/Q ratio and an
assumed friction coefficient µ. This admissible contact angle determines the contact danger zone on
the wheel, where no contact with track components may take place to eliminate the risk of wheel
climbing.
According to experiments described in ERRI C70 RP 1, the contact angle γ shall be no smaller than
A
40°. This corresponds to a friction coefficient of 0,3 and Y/Q of 0,4.
6.3 Wheel profiles and wear
The profiles of both new and worn wheels shall be considered. A typical new wheel profile, according
to EN 13715 is given in Figure 13 for information.
Owing to wear in service, the flange shape will modify significantly, especially the angle of the outside
flange face. Wheel wear is characterised by q . See figure 14. A minimum value of q shall be fixed.
R R
Dimensions in millimetres
Key
R Wheel radius
Figure 13 — Typical new wheel profile
prEN 13232-3:2014 (E)
Dimensions in millimetres
Key
R Wheel radius
Figure 14 — Typical worn wheel profile
For operation on switches and crossings, no sharp edges or burrs may be tolerated in the transition
zone between the active part of the wheel and the flange tip.
6.4 Angle of attack
The angle of attack is the sum of following angles (see Figure 15):
the skew Ψ , due to the clearances present in axle boxes;
the skew Ψ , due to the clearance of the wheel axles in the track;
the skew Ψ , i.e. the angle formed by a curved track and the parallel wheel axles of car or a
bogie;
the geometrical angle of the switch, in switches and crossings, determined at the point where the
wheel hits the switch toe.
prEN 13232-3:2014 (E)
Key
Ψ skew due to clearances present in axle boxes
Ψ skew due to clearance of the wheel axles in the track
Ψ angle formed by a curved track and the parallel wheel axles of car or a bogie
Figure 15 — Angle of attack
6.5 Apparent wheel profiles
The contact point between rail and wheel can be determined by projection of the wheel onto a plane,
perpendicular to the running plane. The projection of the wheel on this plane is called the apparent
wheel profile.
For a wheel with axis perpendicular to the track axis (angle = 0°), the apparent wheel profile is the
same as the cross section of the wheel. See figure 16. Wheel circles become straight lines by the
projection.
prEN 13232-3:2014 (E)
Key
Key
1 Contact danger zone
1 Contact danger zone
Figure 17 — Wheel with angle of attack ≠ 0
Figure 16 — Wheel with angle of attack = 0
Owing to the angle of attack (α ≠ 0°), the apparent wheel profile changes as well as the contact
position between wheel and rail (see Figure 17). The derailment risk is at its greatest when the
contact takes place in front of the wheel as friction forces lift the wheel out of the track.
6.6 Tangent and secant contact
Tangent contact appears when the wheel follows a track element (rail) with a continuous profile.
Secant contact appears when the wheel encounters an object on its route. Typical situations are:
switch toe not protected by its stock rail;
fixed crossing nose in case of insufficient protection by check rail;
switch rail with damaged upper surface (tip).
7 Common derailment-critical situations
7.1 Tangent contact
The contact is similar to plain line contact. The worst case appears when a new profile with maximum
angle of attack encounters the rail. In this case the contact angle γ will be maximum. See Figure 18.
A
prEN 13232-3:2014 (E)
Figure 18 — Tangent contact
7.2 Secant contact at partially open switch tip or crossing nose
The worst case is encountered when the worn wheel hits the switch tip with a positive angle of attack
and when the wheel is in contact with the corresponding stock rail (see Figure 19). There are two
contact points (PC1 and PC0):
prEN 13232-3:2014 (E)
Key
1 PC1 with the switch tip at contact point 1
2 PC0 with the stock rail at contact point 2
Figure 19 — Secant contact
The contact angle in contact point PC1 is to be compared with the limiting value of γ The contact
.
A
point should stay out of the danger zone of the wheel. In Figures 20 and 21 the danger zone is
indicated.
Figure 20 represents a safe situation. Figure 21 represents a situation that is potentially dangerous.
Key
1 Ellipse γ
A
2 Contact danger zone
Figure 20 — Safe secant contact
prEN 13232-3:2014 (E)
Key
1 Ellipse γ
A
2 Contact danger zone
Figure 21 — Dangerous secant contact
7.3 Secant contact at damaged switch tip (for information only)
This situation has been studied in UIC 716.
The worst case appears when a new wheel profile, lifted by 2 mm, encounters the tongue with a
maximum angle of attack (including entry angle). This situation is described in Figures 22 and 23.
Key Key
1 Ellipse γ 1 Ellipse γ
A A
2 Contact danger zone 2 Contact danger zone
Figure 22 — Safe contact Figure 23 — Dangerous contact
prEN 13232-3:2014 (E)
Safe traffic is guaranteed when the contact angle is greater than the limiting value. The contact point
from the damaged switch tip shall lie high enough not to touch the wheel in the danger zone.
This situation has no direct implications on switch and crossing design.
Figure 22 represents a safe situation. Figure 23 represents a potentially dangerous situation.
7.4 Limits
Limits are to be provided by the customer.
For the traffic with UIC-wheels, according to EN 13715 and UIC 510-2, the following limits shall be
respected:
α ≤ 1° (does not include switch entry angle);
max
q > 6,5 mm;
R
γ ≥ 40° (corresponding to Y /Q = 0,4 and µ = 0,3).
A
Customers or networks can request more stringent limits for economical, or maintenance reasons.
8 Output - Functional and Safety Dimensions (FSD)
In the following, FSD’s are shown assuming a zero angle of attack. In calculating FSD’s, the effect of
nonzero angle of attack shall be taken into account.
8.1 Switch panel
8.1.1 Free wheel passage in switches F
WPS
The passing wheel shall not be able to strike the open switch rail. Over the whole length of the switch
the back of the wheel shall not be able to strike the back of the switch rail.
prEN 13232-3:2014 (E)
This situation is represented in Figure 24. The following equation shall be respected.
F < a + b
WPS min min
Key
a minimum value of wheel back-to-back
min
b minimum flange width
min
F free wheel passage in switches
wps
Z stock rail machining reference plane
Figure 24— Free wheel passage in switches
In order to be able to respect this value during operation the design value shall be agreed between
customer and supplier, taking into account tolerances for:
lateral wear on switch rail;
vertical wear on stock rail;
gap between switch rail and associated stock rail;
workshop tolerances;
gauge widening;
geometrical aspects such as inclined switch back machining.
8.1.2 Entry angle
Important entry angles occur when gauge widening is applied to the branch line, i.e. in case of tight
curves (see Figure 25). A similar situation may occur when switch rails are shortened (see Figure
26).
prEN 13232-3:2014 (E)
Key Key
G Track gauge G Track gauge
G1 Gauge widening MP mathematical point of switch
MP mathematical point of switch RP real point of switch
RP real point of switch
θ Switch entry angle
θ Switch entry angle
Figure 25— Tight curve design Figure 26 — Shortened switch design
Both situations may lead to a greater angle of attack, depending also on the track situation in front of
the switch. The limiting angle of attack shall be determined by the customer.
For UIC-wheels corresponding to UIC 510-2, the limits given in the first column of Table 1 apply,
depending on the maximum speed of the branch line. For tracks, designed in accordance to EN
13803-2, this leads to the limits given in the second column.
Table 1 — Maximum angle of attack for UIC-wheels
Maximum angle Maximum entry angle
Speed
of attack (EN 13803-2)
≤ 40 km/h 2° 1°
1,416° 0,416°
≤ 100 km/h
> 100 km/h Reserved Reserved
The actual chosen value shall be agreed between customer and supplier taking into account:
the requested comfort level;
the worst situation that may occur in the adjacent track;
the available turnout length;
maintenance tolerance (i.e. grinding limits of the switch rail);
an acceptable mechanical resistance,
8.1.3 Switch point relief A2
The switch point relief at the switch tip shall be determined such that no contact occurs in the wheel
danger zone. The worst case occurs with new wheel flanges and the switch opened at its limit d
gap
(accep
...
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