Some vehicles may not fit into any of the defined categories; the structural requirements for such railway vehicles should be part of the specification and be based on the principles pre
General
Railway vehicle bodies shall withstand the maximum loads consistent with their operational requirements and achieve the required service life under normal operating conditions with an adequate probability of survival
The railway vehicle body must demonstrate its ability to support necessary loads without experiencing permanent deformation or fracture, as outlined in the validation program specified in Clause 9 through calculations and/or testing.
The assessment will focus on three key criteria: a) the maximum loading capacity that can be sustained while maintaining full operational conditions; b) a safety margin that allows for significant exceedance of exceptional loads before any risk of catastrophic failure; and c) the ability to endure service or cyclic loads throughout the specified lifespan without compromising structural safety.
! d) loads due to re-railing and recovery operations without catastrophic failure."
The specification must include data outlining the anticipated service conditions, which will be used to define all significant load cases in alignment with the acceptance criteria.
NOTE Where appropriate, stiffness criteria as defined in 5.5 should be part of the specification
This European Standard outlines requirements specifically for metallic materials, as detailed in sections 5.4.2, 5.4.3, 5.6, and Clauses 7 and 8 However, if non-metallic materials are utilized, the fundamental principles of the standard must still be adhered to, and appropriate data must be employed to accurately represent the performance of these materials.
The load cases used as the basis of vehicle body design shall comprise the relevant cases listed in Clause 6
All formal parameters are expressed as SI basic units and units derived from SI basic units The acceleration due to gravity g is - 9,81 m/s 2
Categories of railway vehicles
Structural categories
For the application of this European Standard, all railway vehicles are classified in categories
The classification of the different categories of railway vehicles is based only upon the structural requirements of the vehicle bodies
Customers are responsible for determining the appropriate category for railway vehicle design, considering factors such as shunting conditions and system safety measures Variations in customer preferences are anticipated and are not in conflict with this European Standard.
There are three primary categories of railway vehicles: locomotives (L), passenger vehicles (P), and freight wagons (F), each designed with specific construction and objectives These main groups can be further divided into subcategories based on their structural requirements.
The categories for freight wagons are extracted from EN 12663-2
The choice of category from the clauses below shall be based on the structural requirements as defined in the tables in Clause 6.
Locomotives
To this group belong all types of locomotives and power units whose sole purpose is to provide tractive motion and are not intended to carry passengers
— Category L e.g locomotives and power units.
Passenger vehicles
To this group belong all types of railway vehicles intended for the transport of passengers, ranging from main line vehicles, suburban and urban transit stock to tramways
Passenger vehicles are classified into five structural design categories, each encompassing various types of vehicles These categories provide a framework for understanding the different designs and functionalities of passenger vehicles.
— Category P-II e.g fixed units and coaches;
— Category P-III e.g underground, rapid transit vehicles and light railcar;
— Category P-IV e.g light duty metro and heavy duty tramway vehicles;
Freight wagons
All freight wagons in this group are used for the transportation of goods Two categories have been defined:
— Category F-I e.g vehicles which can be shunted without restriction;
— Category F-II e.g vehicles excluded in hump and loose shunting.
Other types of vehicles
Certain railway vehicles may not align with the previously defined categories, such as the standard open bogie van used for transporting motor vehicles, which could be classified as a P-I vehicle It is essential that the relevant category for the structural requirements of these railway vehicles is included in the specifications.
Uncertainties in railway design parameters
Allowance for uncertainties
To address uncertainties, limiting values of parameters or a safety factor, denoted as S, can be integrated into the design process This safety factor is essential for comparing calculated stresses with the permissible stress outlined in section 5.4.
When designing components, it is essential to consider the criticality of potential failures by evaluating the consequences of failure, ensuring redundancy, facilitating accessibility for inspection, enabling effective detection of component failures, and determining appropriate maintenance intervals.
The value of S shall be chosen to include the cumulative effect of all uncertainties not otherwise taken into account.
Loads
Vehicle body design must account for uncertainties in load values The loads outlined in Clause 6 already include this necessary allowance When design loads are based on on-track tests or other information sources, it is essential to incorporate an allowance for uncertainty.
Material
For design purposes, the minimum material property values as defined by the material specification shall be used Where the material properties are affected, for example, by:
— environment (moisture absorption, temperature, etc.);
— welding or other manufacturing processes, appropriate new minimum values shall be determined
The S-N curve, also known as the Woehler curve, is essential for illustrating the fatigue behavior of materials It must account for various influencing factors and represent the lower bound of data scatter as specified in section 7.3.
Dimensional tolerances
Calculations can typically rely on nominal component dimensions, but minimum dimensions should be considered when significant thickness reductions occur due to wear Additionally, ensuring adequate corrosion protection is essential in vehicle specifications, as material loss from corrosion is usually negligible.
Manufacturing process
The performance of materials in real components can vary significantly from that of test samples These discrepancies arise from differences in manufacturing processes and workmanship, which are often undetectable through standard quality control measures.
Analytical accuracy
Every analytical procedure incorporates approximations and simplifications The application of analytical procedures to the design shall be consciously conservative.
Demonstration of static strength and structural stability
Requirement
Calculations and testing must demonstrate that the structure, its individual elements, and equipment attachments will not experience significant permanent deformation or fracture under the specified design load cases This requirement is fulfilled by meeting the yield or proof strength as outlined in section 5.4.2 Additionally, if the design is constrained by ultimate strength or stability conditions, as detailed in sections 5.4.3 and 5.4.4, these must also be satisfied The validation process is further elaborated in Clause 9.
When comparing the calculated or measured stress to the permissible stress, the utilisation of the component shall be less than or equal to 1 according to the following general equation:
U is the utilisation of the component;
R d is the determined result from calculation or test;
S is a design safety factor (see 5.3);
R L is the permissible or limit value
NOTE The equation is sometimes expressed as:
Yield or proof strength
In cases where design verification relies solely on calculations, the factor S1 should be set at 1.15 for each specific load case However, if the design load cases are validated through testing or if a successful correlation between testing and calculations has been established, S1 can be adjusted to 1.0.
Under the static load cases as defined in 6.1 to 6.5, the utilisation shall be less than or equal to 1 as given by the following equation:
S 1 is the safety factor for yield or proof strength;
R represents the material yield (R eH) or the 0.2% proof stress (R p02) measured in newtons per square millimetre (N/mm²), as defined by EN 10002-1, while considering relevant effects outlined in section 5.3.3 Additionally, σ c denotes the calculated stress, also expressed in newtons per square millimetre (N/mm²).
When assessing stress levels in ductile materials, it is not essential to meet the criteria at points of local stress concentration If local stress concentrations are included in the analysis, the theoretical stress may exceed the material's yield or 0.2% proof limit However, the regions of local plastic deformation must be small enough to prevent significant permanent deformation upon load removal Guidance on addressing local stress concentrations in calculations is provided in Annex A, while testing methods are outlined in section 8.2.2.
Ultimate failure
To ensure structural integrity, a margin of safety must be established between the exceptional design load and the failure load This is accomplished by implementing a safety factor \( S_2 \), ensuring that the utilization remains less than or equal to 1, as expressed in the following equation:
S 2 is the safety factor for ultimate failure;
R m is the material ultimate stress, in newtons per square millimetre (N/mm 2 ) (as defined in
EN 10002-1) and taking into account any relevant effects as described in 5.3.3; σ c is the calculated stress, in newtons per square millimetre (N/mm 2 ), under an exceptional load case
Typically, the safety factor \( S_2 \) is set at 1.5; however, a value of \( S_2 = 1.3 \) may be acceptable when design load cases are validated through testing or when a successful correlation between testing and calculations is established Additionally, the safety factor \( S_2 \) can be further reduced if alternative load paths are present and these paths meet the required safety factor standards.
The ultimate failure criterion does not apply for parts of the structure which are specifically designed to collapse in a controlled manner (e.g as required by EN 15227)
The treatment of stress concentration, as outlined in section 5.4.2, is relevant here as well It is crucial to examine the effects of stress concentration more thoroughly in brittle materials, as these materials do not experience local plastic yielding, which is essential for stress redistribution at the concentration points.
Instability
Local instability, in the form of elastic buckling, is permissible provided alternative load paths exist and the yield or proof criteria are met
The vehicle structure must maintain a safety margin to prevent instability that could result in overall structural failure under extreme loads The utilization ratio, defined by the equation provided, should not exceed 1 when comparing the calculated stress or load to the critical buckling stress or buckling load.
S 3 is the safety factor for instability; σ cb is the critical buckling stress, in newtons per square millimetre (N/mm 2 ); σ c is the calculated stress, in newtons per square millimetre (N/mm 2 );
L cb is the critical buckling load, in newtons (N);
L c is the calculated load, in newtons (N)
The safety factor shall be taken as S 3 = 1,5
The instability criterion does not apply for parts of the structure which are specifically designed to collapse in a controlled manner (e.g as required by EN 15227).
Demonstration of stiffness
Stiffness limits ensure that the vehicle body remains within its required space envelope and unacceptable dynamic responses are avoided
Any specific requirements and the means for demonstration of stiffness shall be part of the specification
The necessary stiffness can be determined based on the permissible deformation under a specified load or the minimum vibration frequency These requirements may pertain to the entire vehicle body or to particular components and sub-assemblies.
Demonstration of fatigue strength
General
The structures of railway vehicle bodies are subjected to a very large number of dynamic loads of varying magnitude during their operational life
The impact of loads on a vehicle's body structure is most noticeable at critical features, such as points where loads are applied, including equipment attachments, joints between structural members like welds and bolted connections, and areas where geometric changes create stress concentrations, such as the corners of doors and windows.
The identification of these critical features is essential Detailed examination of local features can be necessary
The fatigue strength shall be demonstrated One of the following methods should be used: d) endurance limit approach (see 5.6.2.1); e) cumulative damage approach (see 5.6.2.2)
Both approaches can be utilized for analyzing predicted and measured stresses from testing and analysis Additionally, other recognized life assessment methods may be incorporated into the design and validation processes when suitable.
The nature and quality of the available data influence the choice of method to be used as described in 5.6.2
In fatigue analysis, if the dynamic load cases account for uncertainties and the minimum material properties outlined in section 7.3 are utilized, there is no need for additional safety factors in the calculations.
Test methods to demonstrate the fatigue performance or to verify the calculations results are described in 8.3.
Methods of assessment
This method is applicable in all scenarios where dynamic stress cycles are below the material's endurance limit If a European or national standard specifies an endurance limit of 10^7 cycles or less, that limit should be applied when considering the loads outlined in sections 6.6 to 6.8 In cases where no endurance limit is provided or it exceeds 10^7 cycles, it is permissible to use the material's fatigue strength at 10^7 cycles as the allowable stress for the loads specified in sections 6.6 to 6.8, as these loads correspond to that cycle count.
The required fatigue strength is ensured when the stress from all relevant combinations of fatigue load cases, as outlined in sections 6.6 to 6.8 or based on measurement results in section 8.3, c), stays below the endurance limit.
This method serves as an alternative to the endurance limit approach, where representative load histories are defined by their magnitude and number of cycles It is essential to consider the combinations of loads acting together The damage from each load case is evaluated using a suitable material S-N diagram (Woehler curve), and the overall damage is calculated based on a recognized damage accumulation hypothesis, such as Palmgren-Miner.
It is permissible to simplify the load histories and combinations, provided this does not affect the validity of the results
To ensure adequate fatigue strength, the total damage at each critical detail must remain below unity (1.0) when considering all relevant combinations of fatigue load cases Additionally, the cumulative damage at these details, based on stress cycles recorded during tests as outlined in section 8.3 c), should also stay below unity when extrapolated to reflect the entire lifespan of the vehicle.
Certain fatigue design codes and standards suggest utilizing a cumulative damage summation limit of less than 1.0 It is essential that the application of this lower value aligns with the specific code or standard being followed.
General
This clause defines the load cases to be used for the design of railway vehicle bodies It contains static loads representing exceptional and fatigue conditions as defined in 5.1
Nominal load values for each vehicle category are provided in the corresponding tables The load values for freight wagons, detailed in the subsequent tables and accompanying explanations, have been extracted from relevant sources.
EN 12663-2 The values represent the normal minimum requirements The vehicle masses to be used for determining the design load cases are defined in Table 1
Table 1 — Definition of the design masses
Design mass of the vehicle body in working order m 1 The design mass of the vehicle body in working order according to EN 15663 without bogie masses
The design mass of a bogie or running gear, denoted as \( m_2 \), includes the total mass of all equipment situated below and including the body suspension Additionally, the mass of the linking elements that connect the vehicle body to the bogie or running gear is distributed between \( m_1 \) and \( m_2 \).
Normal design payload m 3 The mass of the normal design payload as specified in EN 15663
Exceptional payload m 4 The mass of the exceptional payload as specified in
Recovery payload m 5 The mass of the normal design payload as specified in EN 15663 less the mass of any passengers or staff
NOTE For freight wagons the exceptional payload m 4 and the normal design payload m 3 are the same (see
When analyzing and testing structures with distributed loads, it is essential to apply these loads in a way that accurately reflects the real loading conditions, ensuring precision that aligns with the application's requirements and the structure's critical characteristics.
When evidence suggests that alternative design loads or load cases are more suitable than those outlined in this European Standard, the alternative values should be prioritized For instance, if a higher load value is deemed necessary for safe system operation, it must be clearly specified Conversely, a lower load value may be acceptable if supported by a robust technical justification tailored to specific operational conditions or design features.
The design must accommodate all specified load cases from Tables 2 to 18, along with any additional requirements outlined in the specifications Furthermore, it should also support any other pertinent static or dynamic loads, such as engine torque and brake system forces.
Longitudinal static loads for the vehicle body
General
The loads defined in Table 2 to Table 8 shall be considered in combination with the load due to 1 g vertical acceleration of the mass m 1
Longitudinal forces in buffers and/or coupling area
Table 2 — Compressive force at buffers and/or coupler attachment
Locomotives Passenger rolling stock Freight wagons
2 000 2 000 1 500 800 400 200 2 000 a 1 200 a a Compressive force applied to the draw gear stops "c", if this draw gear stop is used (see EN 12663-2)
When the compressive force is applied on side buffers, then half of the value shall be used for each buffer axis
Freight wagons subject to RID crashworthiness regulations shall sustain the maximum loads generated in complying with these requirements (see EN 12663-2)
Table 3 — Compressive force below buffer and/or coupling level
Locomotives Passenger rolling stock Freight wagons
- - - 1 500 a 900 a a 50 mm below buffer centre line
When the compressive force is applied on side buffers, then half of the value shall be used for each buffer axis
Table 4 — Compressive force applied diagonally at buffer attachment (if side buffers are fitted at one or both ends of a single vehicle)
Locomotives Passenger rolling stock Freight wagons
500 a 500 a 500 a - - - 400 400 a This load case applies only if the side buffers are engaged in normal operation
Table 5 — Tensile force at coupler attachment
Locomotives Passenger rolling stock Freight wagons
In certain coupling scenarios, a higher force of up to 1,500 kN may be required, while values can be adjusted to ensure they cover the maximum force developed during normal operations or emergency recovery Specifically, a tensile force of 1,500 kN is necessary for draw gear stop "a" as per EN 12663-2, whereas a tensile force of 1,000 kN is applicable for draw gear stop "b" and other coupler attachment types.
Compressive forces in end wall area
The compressive force specified in Table 6, Table 7 and Table 8 shall be reacted at coupler/buffer level at the opposite end of the vehicle body
Incorporating a crashworthy design in accordance with EN 15227 allows for the application of loads to the vehicle's end wall structure, whether positioned in front of or behind the specified collapse areas.
Table 6 — Compressive force 150 mm above the top of the structural floor at head stock
Locomotives Passenger rolling stock Freight wagons
400 a 400 400 - - - - - a Only applicable for end cabs
Table 7 — Compressive force at the height of the waistrail (window sill)
Locomotives Passenger rolling stock Freight wagons
300 a b 300 b 300 b 300 b - - - - a Only applicable for end cabs b At the driver's cab this load shall be distributed across the windscreen sill.
Table 8 — Compressive force at the height of the cant rail
Locomotives Passenger rolling stock Freight wagons
Vertical static loads for the vehicle body
Maximum operating load
The maximum operating load as defined in Table 9 corresponds to the exceptional payload of the vehicle
Locomotives Passenger rolling stock Freight wagons
1,3 × g × m 1 1,3 × g × (m 1 + m 4 ) 1,3 × g × (m 1 + m 3 ) a a If the application produces a higher proof load (e.g due to dynamic effects or loading conditions) then a higher value shall be applied and defined in the specification.
Lifting and jacking
The forces outlined in Tables 10 and 11 indicate the lifted masses for a two-bogie vehicle This principle can also be applied to railway vehicles featuring different suspension configurations.
The mass to be lifted is determined by the vehicle's mass without payload, except for freight wagons, which are lifted in a laden condition In certain operational requirements, bogies or the full payload may be excluded, leading to values m2 and/or m3 being set to zero or reduced For lifting vehicles of class P-I to P-V with payload, this must be included in the specification.
Table 10 — Lifting and jacking at one end of the vehicle at the specified positions
Locomotives Passenger rolling stock Freight wagons
1,1 × g × (m 1 + m 2 )a 1,0 × g × (m 1 + m 2 + m 3 ) a For passenger vehicles with luggage compartments or luggage areas as defined in EN 15663 the mass m 5 as defined in Table 1 shall be added, i.e 1,1 × g × (m 1 + m 2 + m 5 )
!The other end of the vehicle body shall be supported at the secondary suspension supports restrained in the vertical direction."
Table 11 — Lifting and jacking the whole vehicle at the specified positions
Locomotives Passenger rolling stock Freight wagons
Lifting and jacking with displaced support
In the load case outlined in Table 11, one lifting point must be vertically displaced in relation to the other three supporting points The vertical displacement of this fourth lifting point should be set at 10 mm or equal to the offset that causes lift-off of one of the lifting points, whichever is smaller If required, a greater degree of offset may be included in the specifications.
The EN 16404 standards mandate that vehicle bodies and lifting points possess adequate strength to safely perform re-railing and recovery operations, ensuring compliance with specified requirements.
For freight wagons, the requirements of 6.3.2 and 6.3.3 and consideration of the requirements of 5.4 provide sufficient safety for these recovery scenarios
For vehicles of categories L and P-I to P-V sufficient strength can be proved with one of the following procedures:
For vehicles with air springs, the load case specified in Table 10 must be applied, ensuring that one lifting point is vertically displaced by 10 mm from the other In contrast, for vehicles with different spring types, the load cases in Tables 10 and 11, along with the offset requirement of 6.3.3 (10 mm at workshop jacking pads during full vehicle lifts), combined with the stipulations in section 5.4, offer adequate safety for recovery situations.
NOTE 1 The re-railing and recovery scenarios in EN 16404 include the possibility of one of the jacks sinking by up to
For vehicles lacking air suspension, nearly all twist loading is absorbed by the vehicle's suspension system However, because deflated air suspension typically exhibits high stiffness during recovery, it is essential to account for additional structural twist loading.
An additional local safety factor of 1,5 shall apply for lifting points that
— are predominantly loaded in tension and
— where there is a single load path whose failure would be catastrophic (e.g application of lifting/jacking brackets according to EN 16404:2014, Annex D)
An additional safety factor is required at and around lifting points until multiple load paths are established in the surrounding structure To demonstrate strength, safety factors S1 from section 5.4.2 and S2 from section 5.4.3 can be increased by a factor of 1.5, or the applied loads can be raised by the same factor.
NOTE 2 The increased load capacity at the lifting points compared to the nominal lifting point loads, due to the combination of the dynamic factor of 1,1 given in Table 10, the vertical displacement requirements of the lifting points of 6.3.3 and 6.3.4 and the additional safety factor at the lifting points, is considered to provide an appropriate level of safety against failure for re-railing and recovery operations
Each lifting point must have its maximum vertical force calculated based on the load cases specified in sections 6.3.2, 6.3.3, and 6.3.4 It is essential to demonstrate that the design can support this maximum vertical force, along with a lateral force that is 15% of the vertical force This requirement must be substantiated with a solid technical justification.
It is acceptable to directly evaluate the recovery scenarios 1 to 3 outlined in EN 16404:2014, section 6.3, through analysis or testing This assessment aims to ensure that these scenarios do not lead to the ultimate failure of the vehicle body, and that the lifting points remain stable without deformation that could compromise the safety of the lifting operation.
The yield strength requirement outlined in section 5.4.2 of this standard is not applicable For safety against ultimate failure as per section 5.4.3 and instability according to section 5.4.4, the following values for S2 and S3 should be used.
— for validation based on analyses: S 2 = S 3 = 1,15
— for validation based on tests or with analyses where correlation between test and calculation has been successfully established: S 2 = S 3 = 1,0
NOTE 3 The procedure according to item b) is an alternative procedure It is only necessary to apply it if the procedure described in item a) is not applied."
Superposition of static load cases for the vehicle body
In order to demonstrate a satisfactory static strength, as a minimum the superposition of static load cases as indicated in Table 12 shall be considered
Each part of the structure shall satisfy the criteria of 5.4 under the worst combination of the load cases specified in 6.2 and Table 12
Table 12 — Superposition of static load cases for the vehicle body
Passenger rolling stock Category P-I, P-II, P-III, P-IV, P-V
Compressive force and vertical load – Table 2 and g × (m 1 + m 4 ) Table 2 and g × (m 1 + m 3 )
Table 3 and g × (m 1 + m 3 ) Tensile force and vertical load – Table 5 and g × (m 1 + m 4 ) Table 5 and g × (m 1 + m 3 )
Static proof loads at interfaces
Proof load cases for body to bogie connection
The body-to-bogie connection must support the loads specified in sections 6.3.1 and 6.3.2, as well as those resulting from a 1 g vertical acceleration of the vehicle body mass \( m_1 \) Additionally, it should accommodate the maximum bogie acceleration in the x-direction, with a minimum acceleration of 3 g for motor bogies in category P-I For vehicles operating under heavy conditions, such as during hump hill shunting, higher acceleration values must be taken into account Furthermore, the connection must withstand the lateral force per bogie associated with the exceptional transverse force as defined in EN 13749.
1 g applied on the bogie mass m 2 whichever is the greater.
Proof load cases for equipment attachments
To determine the forces acting on equipment attachments during vehicle operation, the masses of the components must be multiplied by the specified accelerations listed in Tables 13, 14, and 15 Each load case should be applied separately.
The loads resulting from the accelerations specified in Tables 13, 14, and 15 must be evaluated alongside the maximum loads generated by the equipment Specifically, the accelerations in Tables 13 and 14 should be assessed in conjunction with the load from 1 g vertical acceleration, while the load in Table 15 accounts for the equipment's dead weight Additionally, if the equipment's mass or mounting method could alter the vehicle's dynamic behavior, an investigation into the appropriateness of the specified accelerations is necessary.
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
(1 ± c) × g a a c = 2 at the vehicle end, falling linearly to 0,5 at the vehicle centre.
Proof load cases for joints of articulated units
The articulation must support the maximum loads between vehicle bodies, addressing longitudinal, lateral, vertical, and lifting requirements Load cases should be interpreted in line with the articulation's nature and the vehicle bodies' support method For further details, Annex B offers examples of proof load cases.
In order to demonstrate a satisfactory static strength of the articulation joints, as a minimum the superposition of static load cases as indicated in Table 12 shall be considered
For each case the worse of both situations (vehicles in front and rear of the articulation) shall be analysed
Forces and moments at maximum rotations will impact the articulation joint and nearby vehicle structure, corresponding to the minimum curve radius on the operational track Additionally, rotations due to gradient changes must also be considered.
Proof load cases for specific components on freight wagons
The proof load cases for the design of specific components on freight wagons are given EN 12663-2.
General fatigue load cases for the vehicle body
Sources of load input
All sources of cyclic loading which can cause fatigue damage shall be identified
The following specific inputs shall be considered in carrying out the fatigue damage assessment of the vehicle structure.
Payload spectrum
Where the payload does not change significantly, the normal design payload m 3 may be used over the entire operational life for categories P-I to P-V, F-I and F-II
When there are significant changes to the payload, the specifications must clearly define the payloads and the time distribution at each level, ensuring that this information is accessible for calculation purposes.
Significant changes in payload are expected in rapid transit/metro and certain freight applications, necessitating the specification of multiple design payloads based on m³ and/or m⁴ for distinct operational periods In contrast, other vehicle types typically require a constant payload throughout their operational life It is essential to express payload levels as fractions of m³ or m⁴ as applicable, and to consider changes in payload distribution at various mass states when relevant.
Load/unload cycles
To effectively analyze load/unload cycles, it is essential to determine and represent them appropriately Significant fatigue damage can occur when vehicles exhibit a high payload to tare weight ratio, especially with frequent changes in payload.
Track induced loading
Induced loading caused by vertical, lateral, and twist irregularities in the track can be assessed through three methods: a) dynamic modeling using data on track geometry and irregularities; b) measured data from the intended or similar routes; and c) empirical data such as accelerations and displacements.
The nature of the data will differ depending on whether a cumulative damage or endurance limit approach to fatigue design is being used
For a specific vehicle type, previously successful fatigue load cases should serve as the foundation for future designs Alternative load cases should only be considered if there is a compelling reason to justify the modification.
Tables 16 and 17 present empirical levels of vertical and lateral acceleration that align with an endurance limit approach, appropriate for standard European operations These values should be utilized in the absence of more suitable data Additionally, certain applications may specify higher values, and it is important to consider the impact of track twist.
For vehicle classes P-IV and P-V, especially those with low floor designs and limited suspension, the fatigue loads on the vehicle body structure may vary significantly from the values specified in the European Standard It is advisable to obtain acceleration values and interface forces between the vehicle body and bogie through multi-body simulations, prior experience, or test measurements tailored to expected operating conditions Additionally, verifying design assumptions for fatigue strength through on-track tests, as outlined in sections 9.2.3.4 or 9.3.3.4, is recommended in these cases.
The equivalent dynamic loading in a cumulative damage analysis may be represented accordingly by taking the acceleration levels in Table 16 and Table 17 and assuming they act for 10 7 cycles each
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
Category F-II ± 0,2 g ± 0,15 g ± 0,2 g ± 0,4 g a a Applies to equipment attachments, but may be reduced for bogie vehicle and two-axle wagons with improved suspensions
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
The dynamic load factors for operations on grooved rails are defined as follows: for general applications, the formula is \((1 \pm 0.25) \times g (1 \pm 0.15) \times g (1 \pm 0.15) \times g a (1 \pm 0.3) \times g b\), and for freight vehicles with double stage suspension, it is \((1 \pm 0.25) \times g\) In cases where the application results in a higher dynamic load factor due to dynamic effects or specific loading conditions, a higher value must be specified and applied accordingly.
Aerodynamic loading
Significant aerodynamic loads arise in the following circumstances: a) trains passing at high speed; b) tunnel operations; c) exposure to high cross winds
The relevance of such loads shall be considered and a suitable representation of the effects for analysis purposes shall be developed if necessary.
Traction and braking
In general, the number and magnitude of load cycles due to start/stops shall be determined in the specification Unscheduled stops shall be taken into consideration
If no specific data are available the acceleration levels in Table 18, acting for 10 7 cycles, shall be used
In the case of vehicles equipped with magnetic rail brakes the maximum acceleration values used in case of emergency braking shall be considered as a proof load case
The presence of longitudinal accelerations due to dynamic vehicle interactions shall be assessed and their effects incorporated if significant load inputs are generated
Acceleration in metres per square second
Locomotives Passenger rolling stock Freight wagons
Category F-II ± 0,15 g ± 0,15 g ± 0,15 g a ± 0,2 g ± 0,3 g b a If vehicles interface with road traffic then they shall be designed to ±0,2 g b Applies to equipment attachments only.
Fatigue loads at interfaces
General requirements
It shall be ensured that all relevant interface loads are incorporated in a meaningful manner, including the appropriate number of cycles The following clauses define the most important interface loads.
Body/bogie connection
The primary sources of fatigue loads in vehicles stem from traction, braking, and dynamic interactions These loads should be assessed using the methodologies outlined in section 6.6.4, along with the performance characteristics of suspension components such as dampers and anti-roll bars.
Equipment attachments
Equipment attachments must endure loads from vehicle dynamics and additional operational stresses Acceleration levels can be assessed as outlined in section 6.6.4 For standard European operations, empirical acceleration levels for equipment that aligns with the body structure are specified in Tables 16, 17, and 18 Each attachment should be designed for 10 million load cycles.
Couplers
Cyclic loads in coupling attachments resulting from the specified operational requirements shall be assessed if fatigue damage can occur.
Fatigue load cases for joints of articulated units
To effectively demonstrate the fatigue strength of articulation joints in vehicle bodies, it is essential to consider all fatigue load cases specified in sections 6.6 and 6.8 related to the vehicle body structure.
In addition to the loads defined above, the forces and moments generated within the interface components of the articulated joints at rotations between the adjacent vehicles shall be applied
In the event of damage accumulation under typical operational conditions, the movement spectrum can be derived from measurements taken on comparable vehicles and routes, dynamic simulations, or evaluations based on other pertinent data.
Combination of fatigue load cases
Identifying relevant combinations of fatigue load cases is essential to ensure that design requirements are met In certain applications, it may be necessary to consider global loadings from traction and braking cycles, as well as additional loads resulting from longitudinal (x-direction) accelerations, alongside vertical (z-direction) and transverse (y-direction) forces.
An endurance limit analysis must incorporate realistic load case combinations based on the individual loads specified in sections 6.6 and 6.7 When these loads are evaluated together, their magnitudes can be reduced from the values listed in Tables 16 to 18.
Methods for determining suitable load combinations for specific applications are outlined in national or industry standards For instance, the VDV recommendation 152 provides guidance for metros and tramways categorized as P-IV and P-V.
"Structural requirements to rail vehicles for the public mass transit in accordance with BOStrab" is one !of" such standard.)
Modes of vibration
Vehicle body
To ensure acceptable ride quality, the natural modes of vibration of the vehicle body must be sufficiently separated from the suspension frequencies This decoupling is essential to prevent undesirable responses during operation.
Equipment
To prevent undesirable responses, it is essential to sufficiently separate or decouple the fundamental modes of vibration of equipment from the vibration modes of the body structure and suspension during all operational conditions.
Interpretation of stresses
Stress determination for compliance with design standards must align with European or national material standards It is essential to carefully interpret stresses derived from finite element methods or strain measurements, considering whether they represent nominal or geometrical "hot-spot" stresses.
Static strength
The minimum proof/yield and ultimate strengths of materials must adhere to the specified limits outlined in material specifications These values should be sourced from relevant European, International, or national standards In the absence of such standards, the most suitable alternative data sources should be utilized.
Fatigue strength
Data on material behavior under fatigue loading must adhere to current European, International, or national standards, or other equivalent sources when available If verified data is not accessible, it should be generated through appropriate testing methods.
Fatigue strength shall be evaluated using S-N-curves derived in accordance with the following:
— a survival probability of at least 97,5 %;
— classification of details according to the component or joint geometry (including stress concentration);
— interpretation of the limiting values from small-scale samples by the use of a test technique and previous experience to ensure applicability to full size components
The workshop practices and manufacturing control procedures shall produce a product quality consistent with the design data
8 Requirements of strength demonstration tests
Objectives
Tests must be conducted as specified to demonstrate the required strength and stability However, testing may be unnecessary if relevant verification data from prior tests on similar structures is available and still applicable, or if a correlation between testing and calculation methods has been established.
The specific objectives of the tests are:
— to verify the strength of the structure when subjected to the maximum loads;
— to verify that no significant permanent deformation is present after removal of the maximum loads;
— to determine the strength of the structure under loading representing service load cases;
— to determine the stiffness of the structure
The tests shall comprise as appropriate:
— static simulation of selected design load cases;
— measurement of strains/stresses with the aid of electric resistance strain gauges or other suitable techniques;
— measurement of the structural deformation under load.
Proof load tests
Applied loads
For any new vehicle design, it is essential to conduct a series of tests to ensure that there is no permanent deformation of the vehicle body or its components These tests must include assessments of compression loads as specified in Table 2, tension loads outlined in Table 5, vertical loads detailed in Table 9, lifting loads according to Tables 10 and 11, and the most critical combination of load cases identified in Table 12.
It is permissible to verify these load cases by combining the results of individual test cases as appropriate Any requirement for additional test(s) shall be part of the specification
For the other load cases the validation can be performed by analysis or testing, or a combination of both.
Test procedure
Requirements for the static tests:
— the tests shall be carried out in a test rig which allows the application of the test forces at the points where they would occur during operation;
— the vehicle body shall be equipped with strain measuring devices at all highly stressed points, particularly in areas of stress concentrations;
— the positioning of the strain gauges shall be consistent with the method of stress evaluation (e.g nominal or geometrical "hot-spot" stress)
The following shall be measured in preliminary tests and during the actual tests:
— the strains at critical points, such as sole bars, cant rail, corners of the cutouts for access doors and windows;
— the deflection between support points;
To ensure structural stability, it is advisable to preload the vehicle body and apply the maximum force incrementally at least twice, resetting the instrumentation to zero prior to the final test The outcomes of this final test will be crucial for validation purposes.
The stress-strain behavior at the measurement position must exhibit linear characteristics Consequently, the measured residual strains after unloading, denoted as \$\varepsilon_{\text{res}}\$ , should satisfy the criterion: \$\varepsilon_{\text{res}} \leq 0.05 \times R_e / E\$ , where \$R_e\$ represents the relevant parameter.
R is the material yield (R eH ) or 0,2 % proof stress (R p02 ), in newtons per square millimetre (N/mm 2 )
(as defined in EN 10002-1) and taking into account any relevant effects described in 5.3.3;
In areas of local stress concentrations it is permissible for the stress derived from the maximum measured strain to be higher than R provided the behaviour remains linear
In certain situations, applying the full design load is not feasible, necessitating adjustments to the test results to reflect accurate values This can be accomplished by multiplying the test values by the ratio of the design load case to the actual load applied, or through a similar method.
In scenarios where test results stem from combinations of individual test load cases, it is essential to demonstrate compliance with both yield strength and instability criteria.
Service or fatigue load tests
Fatigue tests are essential for vehicle bodies or structural components exposed to dynamic loads, especially when calculations involve critical uncertainties or lack performance data These tests can include laboratory fatigue tests that apply load histories simulating the full operational life of the vehicle, ensuring that load factors and increased cycle numbers are considered to address statistical variations in fatigue strength It is crucial that no cracks develop that could compromise structural safety Additionally, strain measurements can be utilized for fatigue life assessment based on data from static tests, while on-track strain records under representative service conditions can also inform fatigue life evaluations Compliance with the requirements outlined in section 5.6 is necessary for assessments based on these methods.
Impact tests
These tests serve to demonstrate that railway vehicles can remain fully serviceable under normal shunting impacts The tests are optional and shall be included in the specification if required
Objective
The validation program aims to ensure that the vehicle body structure can endure maximum operational loads while achieving the necessary service life under normal conditions, with a high probability of survival It must be demonstrated through calculations, testing, or a combination of both that there will be no significant permanent deformation or fracture of the overall structure or any individual component under the specified design load cases The specifics of the validation program vary based on the originality of the design and its application changes Table 19 provides a summary of the validation program details.
Table 19 — Summary of validation programme
Local or global comparative structural analysis
Static tests Fatigue and/or service tests
New design yes N/A yes only required if other methods do not show sufficient safety
Evolved design and/or new application
Identical design and new application no yes no or reduced test programme only required if other methods do not show sufficient safety
Evolved design, similar application no yes no or reduced test programme no
A new design refers to a product, such as a vehicle or component part, that is entirely original and does not relate to any existing similar products In contrast, an evolved design is based on an existing product and maintains a direct connection to it.
Validation programme for new design of vehicle body structures
General
In order to prove the structural integrity of a newly designed vehicle body structure two major steps are significant: a) structural analyses; b) testing.
Structural analyses
Numerical methods, including finite element analyses, will be employed and may be complemented by hand calculations as needed The analyses conducted will adhere to the load cases specified by this European Standard.
Based on structural analysis results, a railway vehicle can proceed to static, fatigue, or service testing If certain areas of the structure do not initially meet the European Standard requirements, it is permissible as long as subsequent tests demonstrate compliance under representative service conditions.
Testing
Tests shall be performed for all newly designed vehicle body structures as defined in 8.1
Railway vehicle body structures must undergo testing for quasi-static load cases as specified in this European Standard (refer to section 8.2.1) Strain gauges should be strategically placed at key structural positions and critical areas identified through structural analyses The outcomes of the proof load tests must comply with the requirements outlined in this European Standard.
Laboratory dynamic fatigue tests on complete vehicle body structures are not typically standard practice; however, there are situations where such testing may be warranted These fatigue tests can be conducted on particular structural components to ensure they meet the criteria outlined in this European Standard.
To assess fatigue strength, on-track service tests are essential for directly measuring operating stresses and verifying compliance with European Standards when analysis and static testing are inconclusive Strain gauges must be strategically placed on key structural points of the fully equipped railway vehicle, designed for a normal payload of m 3, to accurately capture the structural response under typical service conditions These locations should encompass all critical areas identified through structural analyses and static tests.
An assessment of fatigue strength in key measurement positions and critical areas will be conducted based on these measurements, following section 5.6 as the final step in verifying fitness for purpose.
Validation programme for evolved design of vehicle body structures
General
If a new vehicle body structure is evolved from a proven design the same general process applies but with the modifications as indicated below.
Structural analyses
When a vehicle body evolves from a previously validated design under similar service conditions, earlier data can be utilized alongside comparative evidence However, any areas with significant modifications must undergo re-analysis If the global load path is preserved and stress levels stay within acceptable limits, it is adequate to confirm the acceptability of the changes through analysis alone.
Certain areas of a structure may not meet the requirements of this European Standard, provided that tests demonstrate adequate safety in these areas under representative service conditions.
Testing
Tests shall be performed if it has not been possible to validate the design as indicated in 9.3.2
A static test programme shall be carried out that considers the areas of structural changes and the associated loads
Fatigue tests may be performed as indicated in 9.2.3.3
If analysis or static testing fails to demonstrate compliance with the standard, on-track service tests can be conducted to assess operating stresses and ensure fitness for purpose, especially when a new track presents significantly different loading conditions Additionally, the number of strain gauges used may be fewer than those in the original design measurements.
An assessment of fatigue strength in key measurement positions and critical areas will be conducted based on these measurements, following section 5.6 as the final step in verifying fitness for purpose.
Treatment of local stress concentrations in analyses
The acceptance may be based on one of the following methods: a) Linear elastic analysis
For ductile materials a linear elastic analysis shows that the following criterion for the stress range is fulfilled for each local stress concentration: max min
The inequality \(2R \sigma - \sigma \leq \times S\) indicates that the difference between twice the maximum calculated stress (\(\sigma_{\text{max}}\)) and the minimum calculated stress (\(\sigma_{\text{min}}\)) from all static load cases must be less than or equal to a certain value, with both stresses oriented in the same direction.
R is the material yield (R eH ) or 0,2 % proof stress (R p02 ), in newtons per square millimetre (N/mm 2 ) (as defined in EN 10002-1) and taking into account any relevant effects described in 5.3.3;
S 1 is the safety factor as defined in 5.4.2
For brittle materials the maximum local stress σ c,loc shall fulfil the following criteria based on Neuber's law:
R is the material yield (R eH ) or 0,2 % proof stress (R p02 ), in newtons per square millimetre
(N/mm 2 ) (as defined in EN 10002-1) and taking into account any relevant effects described in 5.3.3;
E is the elasticity modulus; ε end is the endurable total elongation;
S 1 is the safety factor as defined in 5.4.2
The endurable total elongation ε end depends on the ultimate strain A (as defined in EN 10002-1) and is defined as:
0,667 end= ⋅A− e for A < 12,5 %; end=0,05 e for A ≥ 12,5 % b) Nonlinear elastic-plastic analysis
A nonlinear elastic-plastic analysis, utilizing the two extreme static load cases associated with local stress concentration and the safety factor S1, indicates that alternating plastic deformation does not take place Additionally, the residual strains remain within the limits specified in section 8.2.2.
Examples of proof load cases at articulation joints
When satisfying the requirements of 6.5.3 the following load cases are examples that might be appropriate for a simple pivot articulation: a) Longitudinal load F x determined as follows:
The lateral load \( F_y \) is calculated using the formula \( l m J p a \), where \( a_x \) represents the acceleration in the x-direction as per Table 13 The design mass of the vehicle body in working order is denoted as \( m_1 \), while \( n \) indicates the number of bogies attached to \( m_1 \) Additionally, \( m_2 \) refers to the design mass of the bogie or running gear connected to the vehicle body \( m_1 \).
The equation for lateral acceleration at the articulation is given by \$F_y = y^2 \cdot (1 + \omega \cdot Z)\$, where \$a_y\$ represents the effective lateral acceleration, typically set at 1 g The variable \$p\$ denotes the proportion of mass \$m_1\$ that is supported at the articulation, with \$m_1\$ being the design mass of the vehicle body in its operational state The rotational acceleration \$\omega\$ must be calculated under the assumption that the lateral acceleration at the articulation is \$a_y\$ and is 0 g at the subsequent lateral support, such as a bogie or articulation, located at a distance \$l\$.
The rotational inertia, denoted as \( J_{zz} \), represents the yaw inertia around the z-axis, while \( l \) indicates the distance from the articulation joint to the subsequent lateral support, such as a bogie or articulation This article presents three design examples: Example 1 features a design with two articulations, Example 2 includes a design with both an articulation and a bogie, and Example 3 is also discussed Additionally, \( a_y \) refers to the lateral acceleration in these designs.
F y lateral force l distance between articulations ω rotational velocity m 1 mass concerned
Figure B.1 — Determination of lateral load c) Vertical load F z determined as follows
F = + where m 1 is the design mass of the vehicle body in working order of the considered vehicle; m 4 is mass of the exceptional payload
In the worst-case scenario, the second articulated vehicle body is considered empty Additionally, when lifting the body along with the bogies, it is essential to account for the vertical lifting load and the contribution from the adjacent vehicle body, as outlined in section 6.3.2.
Relationship between this European Standard and the Essential
Requirements of EU Directive 2008/57/EC
This European Standard was developed under a mandate from the European Commission and the European Free Trade Association to ensure compliance with the Essential Requirements.
Once cited in the Official Journal of the European Union and implemented as a national standard in at least one Member State, compliance with the specified clauses for high-speed rolling stock, freight wagons, locomotives, and passenger rolling stock, as well as provisions for persons with reduced mobility, provides a presumption of conformity with the Essential Requirements of the Directive and related EFTA regulations.
Table ZA.1 — Correspondence between this European Standard, the HS RST TSI dated June 2006 and adopted by EC on 21 February 2008 and Directive 2008/57/EC
Clause/subclauses of this European
TSI Corresponding text, articles/paragraphs/anne xes of the Directive 2008/57/EC
The whole standard is applicable 4 Characteristics of the subsystem 4.2.2.3.3 Specifications (simple load cases and design collision scenarios) § a Annex A Passive safety – crashworthiness
A.1.1 Detailed mechanical boundary characteristics for the static resistance A.3.4 Protection against a low obstacle
2 Requirements specific to each subsystem
2.4 Rolling stock 2.4.3 Technical compatibility (§3) §5.2, §6.2, §6.3 and §6.4 for category P-II are the transposition in this EN 12663-1 of the mandatory clauses of the
EN 12663:2000 quoted in the TSI
1) The Directive 2008/57/EC adopted on 17 June 2008 is a recast of the previous Directives 96/48/EC "Interoperability of the trans-European high-speed rail system" and 2001/16/EC "Interoperability of the trans-European conventional rail system" and their revision by Directive 2004/50/EC of the European Parliament and of the Council of 29 April 2004 amending Council Directive 96/48/EC on the interoperability of the trans-European high-speed rail system and Directive
2001/16/EC of the European Parliament and of the Council on the interoperability of the trans-European conventional rail
Table ZA.2 outlines the relationship between the European Standard and the CR TSI RST Freight Wagon, originally published in the Official Journal on December 8, 2006, along with its intermediate revision approved by the Railway Interoperability and Safety Committee on November 26, 2008, in accordance with the relevant Directive.
Clause/subclauses of this European
TSI Corresponding text, articles/paragraphs/anne xes of the Directive 2008/57/EC
The whole standard is applicable 4.2.2.3 Strength of Main
Vehicle Structure and Securing of Freight Annex ZZ
Permissible Stress Based on Elongation Criteria Annex Z
Impact (Buffing) Test Annex YY
Strength requirements for certain types of wagon components
Annex N Structure and Mechanical Parts
Permissible stresses for static test methods Annex CC
Annex III, Essential Requirements, General Requirements – Clauses 1.1.1, 1.1.3,
Annex III, Essential Requirements, General Requirements – Clause 1.2 Reliability and availability Annex III, Essential Requirements, Requirements Specific to Rolling Stock Subsystem – Clause 2.4.3 Technical compatibility (§3)
EN 12663:2000 have been transposed into
EN 12663-2 This standard EN 12663-1 provides an alternative method for defining the structural requirements of freight wagon bodies The related annexes of the TSI are covered in EN 12663-2
Table ZA.3 — Correspondence between this European Standard, the CR TSI Locomotive and Passenger Rolling Stock (Preliminary draft Rev 2.0 dated 14 November 2008) and Directive 2008/57/EC
Clause/subclauses of this European
TSI Corresponding text, articles/paragraphs/anne xes of the Directive 2008/57/EC
The whole standard is applicable 4.Characteristics of the subsystem 4.2.2.4 Strength of vehicle structure
2 Requirements specific to each subsystem
The whole standard is quoted and therefore mandatory
The CR TSI Locomotives and Passenger RST is still a draft subject to change without notice
Table ZA.4 — Correspondence between this European Standard, the CR/HS TSI relating to "persons with reduced mobility" (PRM), published in the Official Journal on 7 March 2008 and Directive
Clause/subclauses of this European
TSI Corresponding text, articles/paragraphs/anne xes of the Directive 2008/57/EC
The whole standard is applicable 7.3 Application of this TSI to existing Infrastructure/Rolling Stock 7.3.2 Rolling Stock
2 Requirements specific to each subsystem
2.4 Rolling stock 2.4.1 Safety 2.4.3 Technical compatibility (§3)
EN 12663:2000 is quoted in the TSI but without precise requirements
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard
[1] EN 12663-2, Railway applications - Structural requirements of railway vehicle bodies - Part 2: Freight wagons
[2] EN 15227, Railway applications — Crashworthiness requirements for railway vehicle bodies
[3] BOStrab, Verordnung ỹber den Bau und Betrieb der Straòenbahnen (Straòenbahn-Bau- und
[4] VDV recommendation 152, Structural requirements to rail vehicles for the public mass transit in accordance with BOStrab 3 )
2) May be purchased from Beuth Verlag GmbH, 10772 Berlin, Germany
3) May be purchased from Verband Deutscher Verkehrsunternehmen (VDV), Kamekestr 37-39, 50672 Kửln, Germany.