absolute wheel slide difference between true train speed and circumferential speed 3.1.1.16 relative wheel slide absolute wheel slide divided by true train speed 3.1.1.17 undesired v
Terms and definitions
For the purposes of this European Standard, the terms and definitions given in EN 14478:2005 and the following more specific definitions apply
3.1.1 Wheel slide protection (WSP) terms
3.1.1.1 adhesion profile predefined set of data representing the adhesion characteristics of a section of running line
3.1.1.2 relative air consumption ratio of the total volume of air consumed during a braking stop with WSP activity against that which would be consumed during a stop with no WSP activity
3.1.1.3 auxiliary reservoir protected and dedicated source of pressure energy for local brake actuation and also known as a Brake Supply Reservoir
3.1.1.4 supplementary reservoir pressure reservoir used for determination of relative air consumption
3.1.1.5 crush laden vehicle load condition in excess of the normal fully laden condition that may arise during exceptional operating circumstances
3.1.1.6 low adhesion conditions where the wheel/rail adhesion is insufficient to sustain the required braking rate
3.1.1.7 true train speed v t actual current train speed, also commonly referred to as “ground speed”
3.1.1.8 wheel lock extreme example of wheel slide where the wheel set ceases to rotate during braking, whilst the vehicle is in motion
3.1.1.9 wheel slide condition where a wheel set rotational speed is lower than that corresponding to the true train speed
3.1.1.10 circumferential speed rotational speed of wheel set times radius of wheel
NOTE For vehicles with independent wheels all requirements described for wheelsets apply to the individual wheels
3.1.1.11 reference speed v ref signal generated and generally used by the WSP or WRM (wheel rotation monitoring system) to determine an approximation to the true train speed
3.1.1.12 duty cycle percentage of time which the WSP and brake control element is active compared with the total operational time
3.1.1.13 nominal train speed v specified speed at start of braking during brake tests
NOTE Real speed may slightly differ
3.1.1.14 uncoupled test slip test method of brake testing where the vehicle under test is uncoupled from the rear of the test train and brakes separately
3.1.1.15 absolute wheel slide difference between true train speed and circumferential speed
3.1.1.16 relative wheel slide absolute wheel slide divided by true train speed
3.1.1.17 undesired venting reduction in braking force not justified by behaviour of wheelsets
3.1.1.18 drag braking test test with auxiliary tractive unit performed as a braking with constant brake application and constant speed
3.1.1.19 dynamic brake blending curve curve describing the characteristics of blending of dynamic brake as function of speed
The WSP rack/controller device features a power supply interface that connects to the vehicle's control supply It incorporates electronic hardware and software designed to receive signals from speed sensors and deliver outputs to WSP brake control elements, such as dump valves, which facilitate the modulation of brake cylinder pressure.
WSP dump valve device used to control the amount of air within the brake cylinder in relation to the adhesion level perceived by the WSP controller
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3.1.2.3 speed sensor device used to generate an individual wheelset or wheel speed signal to a WSP controller
3.1.2.4 service interface access point for diagnostic information and maintenance test
Symbols
v nominal train speed (km/h) v ref WSP vehicle reference speed (km/h) v t true train speed (km/h) λ braked weight percentage (%) τ adhesion coefficient σ coefficient of inertia of rotating masses
Abbreviations
BSR brake supply reservoir; for an air brake system with distributor valve, referred to as auxiliary reservoir DNRA detection of non-rotating axle (same as WRM)
ER anticipated event – used in safety analysis
G brake mode G: brake mode used for freight trains with specified brake application time and brake release time
P brake mode: brake mode for passenger and freight trains with specified brake application time and brake release time and specified brake mass percentage
The P(SS) brake mode is designed for both passenger and freight trains, featuring defined brake application and release times It operates with a specified brake mass percentage and includes a self-adjusting load-proportional brake system for enhanced performance.
The R brake mode is designed for passenger and fast freight trains, featuring specific requirements for brake application and release times similar to those in braking mode P, along with a defined minimum percentage of brake mass.
RAMS reliability, availability, maintainability and safety
WRM wheel rotation monitoring system (sometimes called DNRA)
General
A WSP system optimizes adhesion under various operating conditions by carefully managing brake force to prevent wheel sets from locking or sliding due to low adhesion This technology minimizes stopping distances and reduces the risk of wheelset damage, all while maintaining the original performance and functionality of the brakes.
The WSP system and its components must be designed to ensure that their operation, in all modes, does not negatively impact the vehicle, bogie, train, or track.
An additional WRM system shall detect locked wheels, which shall be indicated to the driver, where fitted
This standard gives no rigid specification for service life performance.
WSP controller
The rotation speed of wheelsets is determined using data from sensors and overseen by regulators or automatic control systems These systems send commands to the WSP actuators to adjust the braking force, either by reducing, maintaining, or restoring it as necessary.
The WSP shall be available for operation on braking forces as soon as reference speed is greater than a threshold which is not higher than 6 km/h
The WSP must maintain the required braking force at reference speeds below a specified threshold If the WSP system reduces the brake force, it is essential to restore it to the demanded level.
This reference speed threshold shall not be higher than 3 km/h
The WSP shall not be capable of applying a greater brake force than that demanded
The WSP shall not alter the demanded braking force at standstill except during test
WSP-actuators (e.g WSP dump valves) are able to reduce braking force
All systems must include an independent monitoring or watchdog function that remains continuously active, including during WSP tests, to restore the necessary braking force if there is a sustained brake release Any activation of this function outside of testing must be indicated and logged as a fault Additionally, when the WSP returns to normal operation, the watchdog function should automatically revert to its standby position.
The reliability of the watchdog device shall conform to ER1 in 4.2.3.4
An independent monitoring function, separate from the control algorithm and processor, will enhance the automatic control system This function is designed to prevent the actuator from being triggered if there is an uninterrupted total release of the brake, friction, or dynamic brake, or a combination of these during blending, for a specified duration.
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The monitoring system must ensure that the brake force step is not maintained for more than 10 seconds to prevent errors due to command faults Additionally, the watchdog function will remain active during WSP tests to restore the necessary braking force if there is a sustained release of the brake or if undesired venting occurs after the tests are completed.
4.2.3 Reliability, availability, maintainability and safety (RAMS)
The WSP must be capable of initiating tests to identify various malfunctions or faults It should detect the availability of speed sensors and the electrical circuits of actuators, specifically monitoring for open-circuit and short-circuit conditions Additionally, the system will track every command sent from the control system to the corresponding actuator Upon startup, the WSP will perform an automatic self-check to verify the electrical operational availability of the electronic control unit and its peripherals.
Continuous internal tests specific to the electronic system technology will be conducted to ensure the proper functioning and availability of the WSP, tailored to the unique architecture of each system These tests and monitoring processes will be designed to operate without affecting the vehicle's braking functions and will not compromise the security of the train while it is stationary.
Faults will be indicated by fault codes, which are stored in a fault memory The WSP guarantees that these codes are retained even during power supply failures These fault codes are established through failure analysis and are designed to identify the smallest exchangeable unit.
Separate information on the availability status of the WSP shall be provided for the operational state, in addition to the codes for “Fault” and “OK” indications for maintenance
The initialization and testing processes must ensure that no incorrect information is produced for functions relying on the speed data from the WSP Additionally, the WSP's design should guarantee that non-braking functions do not interfere with its proper operation.
A manual WSP self-test can be initiated while the vehicle is stationary, assessing sensors, actuators, and the electronic control unit's operational availability, along with any existing faults The test sequence includes watchdog tests and complete venting of brake cylinders through release valves/actuators All detected faults during the test can be read, and fault deletion must be confirmed by a subsequent test and indication of proper WSP functionality The manual test sequence will be canceled if the vehicle exceeds 3 km/h, and testing will ensure that no more than 50% of the vehicle's brakes are released simultaneously.
In addition, the above test may be initiated automatically when the vehicle is at standstill
The WSP shall be equipped with a service interface
The reference speed signal must remain unaffected by external functions that utilize it, ensuring the integrity of both the reference signal and the WSP equipment.
A reliability study shall be carried out on the WSP system in accordance with EN 50126-1
The WSP shall be built to a modular design and modules with the same functions shall be interchangeable
Modules which are not functionally interchangeable shall not be able to be physically plugged into the incorrect location
The WSP shall have a safety analysis performed for the following anticipated events (ER):
ER1: Unintended reduction or retention of a brake force on one control channel for a duration in excess of that specified in 4.5
ER2: Failure of any speed output used by a safety critical function (speed-dependent brake force application, electromagnetic track brake)
ER3: Loss of the function indicating a locked wheelset for equipment approved for v > 200 km/h
The hourly probability of these anticipated events occurring shall be calculated by adequate numerical means, e.g fault tree analysis
The WSP system shall be able to operate within the temperature classes as specified by EN 50125-1 inside vehicles and inside cubicles
NOTE EN 50155 applies for electronics
4.2.3.6 Environmental specification and external appearance
The externally mounted WSP components are designed to resist corrosion from typical atmospheric pollutants and function effectively under the conditions outlined in EN 50125-1 Additionally, the WSP control unit complies with the standards set forth in EN 50121-3-1 and EN 50121-3-2.
NOTE Further to EN 50121-3-2 for the WSP system, EN 50121-3-1 applies for the complete vehicle
The dump valve must be designed and installed to safeguard the venting ports from snow and ice If requested by the purchaser, WSP components must demonstrate compliance with this requirement through testing or design documentation Additionally, components installed on the exterior of the vehicle must adhere to these standards.
The installation of WSP system components must prioritize the safety of personnel working within the vehicle, effectively reducing the risk of injuries, such as those caused by sharp edges.
The system shall tolerate permitted differences of the wheel diameter differences on a given vehicle when evaluating speed
4.2.4.2 Special features of WSPs for dynamic and mixed braking systems
The characteristics according to 4.1.1 to 4.2.3 are also mandatory for WSP of dynamic brakes if applicable
Wheel slide must remain within the tolerance limits outlined for friction brakes in Clause 6.4.3.2, especially for tractive units that can utilize dynamic brakes independently of friction brakes, particularly in drag scenarios.
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`,,```,,,,````-`-`,,`,,`,`,,` - brake applications on steep gradients) to prevent damage to the wheel tread and to minimize the influence on speedometer variations
Axle speed sensors
The WSP sensors shall be an integral part of the WSP system
The sensor shall be easy to disconnect for bogie or axle maintenance The sensor should connect into a junction box or should be fitted with a plug `,,```,,,,````-`-`,,`,,`,`,,` -
The WSP dump valve and its connectors must endure the environmental conditions of body or bogie mounting They should meet minimum proof loads corresponding to the inertia forces from accelerations specified in EN 61373, either Category 1 (class A or class B) or Category 2, based on the mounting location It is recommended to increase the vibration levels by a factor of 3 for vertical loads and by a factor of 4 for longitudinal and lateral proof loads for axle-mounted sensors, compared to the standards outlined in EN 61373.
The component must achieve a fatigue life of at least 10 million cycles, ensuring a failure probability of no more than 2.5%, while withstanding the inertia forces linked to the specified mounting location accelerations.
Compliance may be demonstrated by design and test documentation.
Dump valves or other device with a similar function
The braking force is regulated through WSP dump valves or other pneumatic control devices, which manage the venting, holding, and filling of the brake cylinder under the supervision of the WSP control unit.
The vehicle's pneumatic interface will utilize a manifold, allowing for the removal of the dump valve without disrupting the existing piping Additionally, the pipe connections will adhere to standard pipe thread specifications.
EN ISO 228-2 Chokes should be mounted in the bracket of the dump valves
The diameter of the pipes has to be attuned to the nominal width of the dump valves
The connector for the dump valve shall be at least to IP67 in accordance with EN 60529:1991
The WSP dump valve and connector must be durable enough to endure the conditions of body or bogie mounting It should also be capable of withstanding proof loads from inertia forces linked to accelerations specified in EN 61373 Categories 1 and 2, as well as EN 50155 standards.
It shall have a fatigue life of not less than 10 7 cycles with a probability of failure of not more than 2,5 %, under the inertia forces associated with the following accelerations
Compliance may be demonstrated by design and test documentation
The WSP dump valve is designed to prevent significant air loss from the brake cylinder to the atmosphere It must not leak more than 0.01 Nl/min when tested at a pressure of 7 bar within the temperature range of -25 °C to +70 °C, as specified in subclause 5.5.5.1.
Between – 40 °C and – 25 °C a WSP dump valve shall have a leakage rate of not greater than 0,1 Nl/min when tested at a pressure of 4 bar in accordance with subclause 5.5.5.2
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Dump valves must not hold more than 0.1 bar in the brake cylinders when de-energized and the brakes are released Additionally, the WSP system should prevent the vent and fill passages from being open at the same time.
The dump valves shall be an integral part of the WSP system.
Power supply
In vehicle design, it is essential for the WSP to include a standby power option, ensuring that the WSP activates and has power available when the vehicle is in motion The functionality of WSP systems relies on a reliable power supply, which can be sourced from the vehicle or generated by the WSP itself.
WSP systems shall be designed to function correctly allowing for fluctuations in voltage as permitted in
According to EN 50155, Clause 3.1.2, if voltage fluctuations exceed specified limits, the WSP must either continue to operate normally or shut down without disrupting connected systems, such as the brake and door control systems In the event of a shutdown due to voltage fluctuations, the WSP is required to automatically resume normal operation once the supply voltage returns to the acceptable range Furthermore, if the WSP does not provide its own power, it will remain unaffected by the voltage fluctuations allowed under EN 50155, Clause 3.1.2.
The WSP installation for friction brake shall have its own protected electrical circuit except if it is an integrated part of the brake control
Power supply for WRM shall be protected by its own circuit breaker in order to make it independent
A WSP installation on a non-powered trailing vehicle must have its own protected circuit, with fuses or circuit breakers distinctly separated from others to prevent confusion The WSP should receive power whenever available, and automatic supply cut-off is only allowed during sleep mode or for battery protection in cases of degraded battery conditions or low voltage due to prolonged lack of supply.
Air supply
The WSP is designed to minimize additional air consumption during operation, ensuring that the vehicle's air equipment is appropriately sized so that the WSP does not negatively affect the pneumatic brake performance Specifically, the WSP operation must not cause BSR pressures to fall below the required brake application pressure Additionally, the WSP can be disabled if the BSR pressure drops below a predetermined level For vehicles with limited air supply, such as single brake pipe freight wagons, the WSP will be turned off when the Brake Supply Reservoir (AR) pressure reaches the minimum emergency brake pressure.
It shall be possible to operate the WSP dump valve or control device without restrictions with compressed air quality according to the following classes defined by ISO 8573-1 or better:
Class 4 – for the maximum particle size and the maximum concentration of solid contaminants;
Class 4– for the water dewpoint;
Class 4 – for the maximum total oil concentration (droplets, aerosols and vapours)
Where the WSP components are designed only for use in a “dry” system, it is permissible for the compressed air quality to be changed to ISO 8573-1, Classes 2-2-2
Any specific fire requirements for the WSP system for particular lines or train services shall be observed The fire requirements shall be tested in accordance with that specification
General
5.1.1 Type testing and vehicle implementation testing - general
The WSP system will undergo type testing through a combination of vehicle track tests and validated simulator testing that accurately reflects track conditions, vehicle parameters, and adhesion levels This testing must be validated against real-world results, and the laboratory housing the test facility must be accredited according to EN ISO/IEC 17025, meeting the requirements outlined in Annex A.
The simulator testing (type test) may be replaced partially by track test on a vehicle
A track test, as part of the vehicle implementation test, shall be performed except where there is previous evidence of track testing
The requirement for re-testing (type-test) if hardware or software is modified, is derived from EN 50128
Testing will encompass various vehicle types, including coaches, wagons, and tractive units, tailored to the specific applications of the equipment Slip tests will be conducted based on the guidelines outlined in Tables 3, 4, and 5, which vary according to vehicle type and speed The simulator facility must be equipped to test a diverse array of vehicle types and conditions.
The general design requirements for the simulator facility are identified in Annex A
5.1.3 Ambient temperature for track testing
WSP vehicle tests must be conducted at moderate ambient temperatures ranging from 5 °C to 25 °C and are prohibited in snowy conditions Additionally, the rail surface temperature should be recorded after each test, ensuring it remains between 5 °C and 35 °C.
To ensure optimal brake performance, it is essential to verify that the auxiliary reservoir supplies adequate air, achieving maximum pressure in the brake cylinders across all brake positions under dry conditions.
Overview of required test programmes
The function of the WSP shall be tested as in Table 1 below:
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Table 1 — Testing of the function of the WSP system Vehicle category
Tests required as set out in Table Additional subclauses
Multiple units (e.g commuter, regional railway trains) 5 4.1; 6.4; 6.4.2; 6.4.3; 6.4.3.2; 6.4.3.3; 6.4.3.4 a ;
6.4.3.6 b ; 6.4.3.7; 6.4.4.4 a Test facility simulation possible b For adhesion-independent brakes
Tests on simulation rig
Simulator facility tests should be utilized, when technically feasible, for both the verification process and the validation of WSP changes These tests aim to minimize the need for track tests and are especially beneficial for specific requirements.
1) initial optimization of the WSP equipment prior to any track testing;
2) as a replacement for track tests which present operational difficulties, for example, high speed tests, or operational track access limitations;
To adjust the WSP parameters, modifications are necessary when there are changes in vehicle design, particularly when there are notable differences in wheelset inertia between a trailer vehicle and a motored vehicle of the same basic unit type.
4) to modify the WSP parameters when the WSP is used on a different type of vehicle than that for which it was originally approved;
5) to evaluate the implication of sanding or other system that could impact upon the WSP performance;
6) as part of a post incident investigation
The design requirements for simulation facilities are set out Annex A
This subclause details the simulation testing of WSP systems The performance criteria that are to be met by the WSP system under evaluation are outlined in 6.3.1 and 6.3.2
Before starting the testing program, it is essential to validate the accuracy of the vehicle model simulation by comparing the predicted braking performance from the computer model with actual track test data.
The validation of this specific type of rolling stock must ensure that the simulation can accurately detect behaviors that may arise from communication between WSP units in a train These functions should be tested during the vehicle implementation test unless the simulator can replicate the entire train segment relevant to WSP control.
The simulation validity test must be conducted on an adhesion profile that consistently exceeds the adhesion level required for the vehicle's maximum braking rate, simulating good, dry conditions In cases where track test data is not available, such as with new rolling stock, the predicted or calculated dry rail stopping distances from the train braking designer or supplier can be utilized for the validation process.
The adhesion profile shall be described in terms of the coefficient of railhead friction against distance along the running line This will vary with the level of wheel slide
Tests must be conducted for at least one vehicle condition (tare/laden) for each vehicle type, using a braking speed determined from track test measurements or calculations based on the train's maximum operating speed A vehicle model simulation is considered acceptable if the predicted stopping distances align within ± 5% of the dry rail stopping distances obtained from track tests or calculations provided by the braking equipment suppliers.
For simulation testing it is highly desirable to be able to recreate the characteristics of:
3) presence of water (moisture, mist, drizzle; etc)
As the wheels of the vehicle on test slip, they modify the adhesion level between wheel and rail so it will be necessary to re-create this conditioning effect
Values of adhesion shall be from 0,06 to 0,08.
Test of WSP-controller
Test vehicles must isolate any brakes that do not rely on wheel/rail adhesion For certain tests, these brakes need to be activated, and the Wheel Slide Protection (WSP) system must function correctly Additionally, the test vehicle or validated test facility should feature a brake system that accurately represents the system for which the WSP was designed, whether it involves disc, block, or dynamic braking.
The following shall be measured/recorded as a minimum during all the testing of the WSP system:
2) rotational speed of individual axles;
3) brake cylinder pressures/forces measured downstream from the valves of the WSP and brake force of the dynamic brake,
5) energy storage for braking (for example, for air braking - auxiliary reservoir/BSR pressure);
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8) activation of the dump/control valves;
11) reference speed v ref if used for WSP regulation or external systems;
12) pressure of main air supply;
16) rail temperature and ambient temperature;
17) circumferential speed of all wheelsets In trainsets, all wheelsets that can be relevant depending on the WSP design;
18) pressure in the auxiliary air reservoir or BSR at the beginning and at the end of the brake application (in the case of slip tests);
20) additional command signals (magnetic track brake, doors, sanding, dynamic brake inhibit, etc.);
21) input signals (availability of dynamic brake, other vehicle status information, etc.);
22) output signals (doors, magnetic track brake, sanding, dynamic brake inhibit, etc.)
The following variables shall be measured:
24) rail temperature and ambient temperature, measured after the test.
Actuator tests
Component type testing shall be performed on a single component issued from the serial production All components of WSP system are subject to the type test
All type tests must be conducted at a temperature of (20 ± 5) °C, using compressed air quality class 4-4-4 as per ISO 8573-1:2001, unless the WSP components are intended for a "dry" system, in which case a quality of 2-2-2 is acceptable Additionally, unless stated otherwise, tests marked with an asterisk (*) should be performed at the temperature specified in EN 50125-1, with an upper limit of 60 °C and across a broader temperature range.
Tests shall be performed in the order shown in Table 2
Table 2 — Operations to carry out for qualification
Tests Corresponding standard sub- clause
5.5.4 Check of physical and geometrical characteristics
The requirements outlined in subclauses 4.4.2.1, 4.4.2.2, 4.6.2, 4.3.1, and 4.3.2 must be verified using suitable measuring instruments, following the specifications and the manufacturer's drawings Additionally, threaded connections should be assessed using GO/NO-GO gauges.
Pass/fail criteria: The result is satisfactory if all the specified characteristics are met
The WSP dump valve undergoes leakage testing at a feed pressure of 4.0 bar when completely de-energized, as well as in a hold position with output pressures of 0.5 bar and 3.0 bar.
This test shall be performed at (20 ± 5) °C and (- 25 ± 1) °C
Pass/fail criteria: No leakage to atmosphere greater than 0,01 Nl/min
The WSP dump valve undergoes leakage testing at a feed pressure of 4.0 bar when completely de-energized, as well as in a hold position with output pressures of 0.5 bar and 3.0 bar.
This test shall be performed at (- 40 ± 1) °C
Pass/fail criteria: No leakage to atmosphere greater than 0,1 Nl/min.
In-service monitoring
Where required by the Railway Undertaking, in-service monitoring of satisfactory system performance shall be performed on at least 5 vehicles over a period of one year
In-service monitoring is only necessary as part of the equipment's type test and is not required if the equipment has already passed a successful in-service test with another Railway Undertaking This requirement applies to both new components and systems.
The parameters to be monitored shall include:
2) open circuit/short circuit dump valves and speed sensors;
4) conditions of low air and excessive stopping distances;
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In cases where in-service monitoring is requested, the lack of such monitoring will not hinder the preliminary approval of the equipment or vehicle, as long as the equipment has successfully met the type test requirements outlined in this specification.
A "pass" indicates certification of the WSP system, while a "fail" will prompt an assessment to decide whether to rectify the issue and continue or to rectify and repeat the entire period.
Pass/fail criteria: satisfactory performance and reliability of component(s)/system, which shall include there being no wheel damage that can be attributed to the WSP equipment.
General
The testing schedule will be based on the application and the vehicle contract related to the WSP equipment installation This document outlines the essential mandatory tests, customer-specific tests, and additional tests that may be required by the contract.
A track test, as part of the vehicle implementation test, shall be performed except where there is previous evidence of track testing
6.1.2 Ambient temperature for track testing
WSP vehicle tests must be conducted at moderate ambient temperatures ranging from 5 °C to 25 °C and are prohibited in snowy conditions Additionally, the rail surface temperature should be recorded after each test, ensuring it remains between 5 °C and 35 °C.
To ensure optimal performance during tests, it is essential to verify that the auxiliary reservoir supplies adequate air, achieving maximum pressure in the brake cylinders across all brake positions under dry conditions.
Overview of required test programmes
Table 3 — Type test programme for coaches
Type of brake test Initial test speed km/h
Rail condition Stopping distance limit
Number of tests according to 6.4.4.2
120 Without Dry rail 580 < s < 620 m Number of tests according to 6.4.4.2
3 R EB to stop 160 With Dry rail This test is to show that there is no WSP activity on dry rail
4 RR EB to stop 160 With Dry rail 720 m < s <
Number of tests according to 6.4.4.2
5 R EB to stop 120 Without Sprayed rail s < 700 m Minimum number of tests: 4 (6.4.4.5.2) Not any case "A" allowed
6 P EB to stop 120 Without Sprayed rail s < 730 m Minimum number of tests: 4 (6.4.4.5.2) Not any case "A" allowed
7 R EB to stop 160 With Sprayed rail s < 1350 m Minimum number of tests: 4 (6.4.4.5.2) Not any case "A" allowed
8 RR EB to stop 160 With Sprayed rail s < 1250 m Minimum number of tests: 4 (6.4.4.5.2) Not any case "A" allowed
9 R EB to stop as uncoupled test or as test with coupled unbraked locomotive
120 With 1 kg soap distributed over
With Sprayed rail – Full application
11 R EB to stop as uncoupled test or as test with coupled unbraked locomotive
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NOTE The brake position RR is applied only for the approval of wheel slide protection device and corresponds to a theoretical value of λ = 190 - 205 %
Table 4 — Type test programme for wagons
1 P (SS) 120 Tare Without Dry rail 560 m < s < 600 m Number of tests according to 6.4.4.2
Without Dry rail 700 m < s < 730 m Number of tests according to 6.4.4.2
3 R 120 Tare Without Dry rail 440 m < s < 490 m Number of tests according to 6.4.4.2
Without Dry rail 520 m < s < 540 m Number of tests according to 6.4.4.2
Without Dry rail This test is to show that there is no WSP activity on dry rail
6 P (SS) 120 Tare Without Sprayed rail s < 730 m Minimum number of tests:
Without Sprayed rail s < 800 m Minimum number of tests:
8 R 120 Tare Without Sprayed rail s < 700 m Minimum number of tests:
Without Sprayed rail s < 700 m Minimum number of tests:
With Sprayed rail s < 1 250 m Minimum number of tests:
With 1 kg soap distributed over 20 m, 200 m after brake initiation
With Sprayed rail – Drag test
6.2.3 Test programme for tractive units and trainsets
Table 5 — Type test programme for tractive units and trainsets
Spraying of rail Adhesion Stopping distance criterion
1 120 Dry rail reference for extension of stopping distance at 120
Number of tests according to
2 Maximum speed a Dry rail reference for extension of stopping distance at maximum speed
Number of tests according to
3 120 Sprayed rail the greater of 700 m or 125
% of the dry stopping distance
4 Maximum speed a Sprayed rail the greater of 700 m or 125
% of the dry stopping distance
20 m, 200 m after brake initiation, otherwise dry rail
Stabilized drag test with dynamic brake for 30 s, all wheelsets shall slide
Stabilized drag test with dynamic brake for 30 s, all wheelsets shall slide
8 50 Sprayed rail – Full application a Where maximum speeds exceed 160 km/h, it is permissible to replace maximum speed tests with tests at 160 km/h together with supplementary tests in 6.4.3.6
NOTE 1 The reason for the 125 % criterion is that there are train sets with a braking rate less than λ = 120 %
NOTE 2 For MU test according to line 6 and 7; some wheelsets may be isolated from braking in order to reduce required tractive power
NOTE 3 If the maximum speed is less than specified in one of the lines of the table then use the maximum speed
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Tests on simulation rig
6.3.1 General (Programme and criteria of simulator facility tests)
To validate a WSP, the simulator test shall be performed as given in Table 6
Table 6 — Programme of criteria of simulator facility tests Test Criteria (Mandatory) Additional Results
Tables 3, 4 and 5 Maximum slide Stopping distance (extension)
No locked axles Air consumption
No undesired venting 1) Tests at maximum speed No locked axles Stopping distance (extension)
Up to 200 km/h + 20 % No undesired venting Air consumption
Up to 350 km/h + 10 % Maximum slip Verification of reference speed
Drag braking tests No locked axles Maximum slip
(τ = 5 % at v = 100 km/h for 30 s) No undesired venting Verification of reference speed
At least at its maximum speed No activation of watchdog device Air consumption
Low adhesion tests No activation of watchdog device Maximum slip
(τ = 2 % at v = 120 km/h for 120 s) No locked axles Verification of reference speed
At least at its maximum speed No undesired venting Air consumption
Dry tests on rising and falling gradient No undesired venting
Reduced adhesion tests on rising and No activation of watchdog device Verification of reference speed falling gradient (5 %) No undesired venting
No locked axles Fault detection (speed sensors and Locked wheelset signal valves open circuit and shortcircuited) Conformance to this specification
Conformance to manufacturer’s technical data
Watchdog device Locked wheelset signal
Conformance to this specification Conformance to manufacturer’s technical data
1) Undesired venting: reduction in braking force not justified by behaviour of wheelsets
Values of adhesion shall be from 0,06 to 0,08
6.3.2 Measurement and pass/fail criteria
Where the train speed is greater than 30 km/h, there shall be no wheel locking
Where the train speed is less than 30km/h, there shall be no wheel locking greater than 0,4 s duration
1) V > 30 km/h – no lock ups; and
2) 5 km/h < V > 30 km/h – no lock ups longer than 0,4 s
For adhesion levels < 0,06 (peak) and speeds > 5 km/h a single lock up of the wheel shall transfer an energy lower than 26 kJ per contact point
Total energy (W) per wheel generated by one single lock up:
F axle load; td duration of lock
Typical example for the margin of 26 kJ:
The peak of the slide must not drop below 25% of the instantaneous speed for more than three seconds when the train is traveling at speeds between 120 km/h and 160 km/h, or at 30 km/h if the instantaneous train speed is 120 km/h or lower.
This criterion refers to 6.3.1, Table 6, row 1 and 2
This requirement is applicable to 6.3.1, Table 6, row 1
Relative air consumption shall not exceed the limits defined in Table 7
Table 7 — Limits for relative air consumption Speed Relative air consumption
6.3.2.4 Extension in stopping distance limits
The stopping distance limits are determined according to the vehicle type and hence the test programme selected Refer to tables 3, 4 and 5 for more details
In addition to mandatory tests, railway administrations and operators may conduct additional testing to enhance the performance of the Wheel Slide Protection (WSP) system for specific routes Infrastructure managers might also establish mandatory network access criteria However, in certain member states, a standard track-based approach to optimizing WSP may not adequately protect against wheel damage during service use.
Member states may mandate specific country tests utilizing simulations based on actual leaf film under both variable and constant adhesion conditions These assessments aim to evaluate the performance of the WSP system at adhesion levels consistently lower than those specified in section 6.4.
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`,,```,,,,````-`-`,,`,,`,`,,` - member states may even require additional tests as part of route acceptance The country specific test information in Annex B is provided as an example of UK's best practice
The additional tests for route acceptance are defined in Annex C
Evaluation against variable adhesion profiles that have been obtained from actual service conditions have improved the optimization of the WSP system and reduced the levels of wheel damage seen
The WSP is utilized in certain train installations to manage external devices, such as door systems It is beneficial to evaluate the WSP's control over these devices through a limited set of tests Additionally, specific systems like sanding systems that directly interact with WSP operations should also be tested to assess their impact on WSP performance These optional tests are detailed in section 6.3.3.
The pass/fail criteria identified in Annex B are based upon values representing best industry practise in the
In the UK, test limits are established based on profiles derived from direct track measurements using a tribometer train Alternative methods, such as artificial profiles or other track measurements, may yield varying adhesion profiles, necessitating different test limits If a tribometer train is not utilized, it is essential to provide documentation demonstrating that the datasets accurately reflect the full range of measured values and the variability of naturally occurring low adhesion.
The tests are designed to simulate a variety of adhesion profiles that closely mimic real service conditions It is essential to include profiles that represent a broad spectrum of adhesion levels: normal (above 0.1), low (0.05 to 0.1), and very low (below 0.05), which can vary continuously along the track To enhance the rigor of the WSP test, some profiles should begin with low or very low adhesion and transition to higher adhesion, while others should do the opposite The rate of adhesion change along the track must realistically reflect the variations experienced in service, such as when a train transitions from a damp, leafy cutting to an open area with a dry railhead.
Adhesion profiles cannot be classified by a single adhesion value due to their variable conditions Instead, they are best categorized based on their severity and frequency of occurrence, which are divided into three distinct groups.
Category 1 - most frequent but least severe, giving rise to stopping distances less than 1 545 m;
Category 2 – less frequent but more severe, giving rise to stopping distances between 1 545 - 1 745 m; Category 3 – least frequent but most severe, giving rise to stopping distances in excess of 1 745 m
The datasets are classified based on the braking distance of a standard 4-axle passenger coach, as defined by EN 15179 This vehicle model utilizes an idealized Wheel Slip Protection (WSP) system, maintaining a constant slip of 5% while decelerating from a speed of 145 km/h to a complete stop.
The selected track adhesion profiles are used to establish if the WSP equipment:
1) makes effective use of the available adhesion (minimal stopping extensions);
2) minimizes wheel damage (no wheel locks/minimal Martensitic wheel damage from gross wheel slide);
3) makes efficient use of the installed air capacity (minimal air consumed);
4) demonstrates good regulation of internal WSP speed reference (prevents unnecessary venting)
These criteria are described in more detail in Annex B
There are optional tests that may be carried out on the WSP system for sanding systems, dynamic brake interfacing and peripheral equipment that are specified detailed in Annex C
A simulation facility shall fulfil requirements according to Annex A.
Tests on the vehicle
The variables listed in 5.4 shall be recorded simultaneously on a test vehicle equipped with the WSP under investigation, and shall be represented graphically as a function of time
The weather conditions and distance as function of time for each test shall be indicated in the report
The relative air consumption of the WSP must be calculated for each test and documented in the test report This calculation can follow the method outlined in section 6.4.4.4 or utilize a direct calculation based on the evolution of brake cylinder pressure during braking, as illustrated in Figure 4 In this scenario, a supplementary reservoir is not required since the air shut-off cock remains open.
During testing, it is essential to monitor the additional switching signals provided by the WSP for auxiliary functions, both with and without spraying, to ensure accurate assessments of performance on sprayed and dry rail conditions.
It is recommended that an odometric signal be recorded in a way that enables the distances covered to be determined
A typical diagram showing the various stages of such a braking test can be seen in Annex D
During the tests, the impact of the adhesion-independent brake must be documented as a signal or energy component, particularly if the braking force cannot be measured This documentation can be represented through a digital or analog signal, such as excitation current.
The conditions in 5.4 and 6.4.3 shall apply A variable that is proportional to the dynamic braking force (e.g motor current) shall be recorded during the tests
To minimize adhesion, an aqueous solution of biodegradable detergent with a fatty acid or surfactant base should be used, ensuring a concentration below 15% and free from mineral fillers This detergent must easily mix with water and be safe for disposal in the track.
To achieve the desired adhesion rate (\$τ_a\$) between 0.06 and 0.08 during initial braking, the detergent concentration must be at least 1 liter per 100 liters of water The solution should be dispensed in front of each wheel of the first wheelset at a flow rate of 0.12 to 0.19 l/min through 8 mm diameter nozzles, positioned no more than 70 mm from the rail and wheel Intermittent activation of the spraying device will create varying adhesion coefficients.
The evaluation method for the tested level of adhesion is described in 6.4.4.3 and Figure 3, which covers the evaluation of slip tests
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WSP performance shall be evaluated in a series of braking tests on tangent track, the recommended maximum gradient being of ± 5 ‰ with a maximum value of ± 10 ‰
Before each test series, which can include up to 10 consecutive tests, the test vehicle's wheels must be regenerated if the initial braking speed exceeds 100 km/h This regeneration is necessary to restore the typical braking conditions over a distance of at least 20 km Tests should ideally be conducted on various sections of the line If tests must occur on the same section, scheduled interruptions are required to allow normal adhesion conditions to be reinstated through train movements or other methods.
A braking test must be conducted at a speed of 100 km/h on a track section of at least 500 meters with adhesion levels below 3% This test can be executed by applying oil or soap to the track, or by simulating conditions in a testing facility During the test, under low adhesion conditions (τ < 0.03), the Wheel Slide Protection (WSP) system must prevent the wheels from locking for more than 0.4 seconds.
An emergency braking test must be conducted at a speed of 100 km/h, or at the maximum speed if it is lower than 100 km/h This test should take place on a track section that is at least 500 meters long, or shorter if the maximum speed is reduced.
To simulate rail head conditions for track tests at speeds of 100 km/h with adhesion levels between 2% and 3%, one can use oil, soap, or a biodegradable substitute like paper tape on the rail While a test rig can replicate these conditions, a track-based test is essential for high-speed WSP operations.
The WSP shall not allow the wheels to lock
The brake point must be established to ensure that the brake force is fully engaged at the start of the treated track, and the assessment of this test is specific to the treated track.
Braking performance on dry rail must be assessed according to this specification, with the necessary performance metrics under dry conditions (excluding WSP action) detailed in the provided tables for various brake positions.
Coaches and trainsets shall be tested unloaded
The relative air consumption of the WSP must be calculated for each test as per section 6.4.4.4 and should not exceed the limits specified in Table 8 It is important to ensure that the evaluation of air consumption excludes any usage from other equipment, such as secondary suspension systems.
To ensure that the pressure in the auxiliary air reservoir does not fall below the maximum cylinder pressure during replenishment tests, a supplementary reservoir must be installed.
During slip tests, it is essential to spray the rails approximately 300 meters before the braking point and along the entire braking distance, with a reduced distance of 100 meters for tests conducted at 50 km/h.
Proof of the test at a speed of 50 km/h may be furnished by the slip test method or by using a coupled, but unbraked locomotive
A further test shall be performed on dry rail, at a braked mass percentage, λ, for approximately 150 % and from a speed of 120 km/h, with approximately 1 kg soap or other substances previously described in 6.4.2.2
30 on each rail previously distributed regularly over each rail 200 m behind the brake application point over a length of at least 20 m
During testing, it is essential that none of the wheelsets lock at speeds exceeding 30 km/h Additionally, any wheel locks occurring below this speed must not exceed a duration of 0.4 seconds Specifically, wheel locks that happen at true train speeds between 5 km/h and 30 km/h should also be limited to a maximum of 0.4 seconds.
The absolute wheel slide for the wheelsets shall not exceed the following values for more than 3 seconds:
1) 25 % of the instantaneous speed if this is between 160 km/h and 120 km/h;
2) 30 km/h at an instantaneous speed ≤ 120 km/h
The relative air consumption of the WSP as calculated in 6.4.4.4 may not exceed the following values for main line railways
Table 8 — Speed and relative air consumption for main line railways
NOTE 1 This is not a specification for sizing of air reservoir
NOTE 2 The air consumption at varying adhesion conditions can be much higher
No undesired venting is permitted