EN 14067 Railway Applications - Aerodynamics

The European standard “EN 14067 Railway applications - Aerodynamics” consists of the following sub-sections published under the same title:

• The standard “EN 14067-1 Part 1: Symbols and units” applies to the field of aerodynamics for railway applications. This standard defines the symbols and units used in formulas and calculations in the field of aerodynamics. The definitions given in this standard explain the symbols and classify the units. However, these symbols may not have the same significance in a different application area. Additional symbols should be defined according to the application.

This standard provides uniformity in engineering studies, simulations, tests, and documentation in the field of railway aerodynamics. It applies generally to aerodynamics for railway applications. It defines the following:

• Key symbols (e.g., for velocities, pressures, forces, coefficients, reference fields, densities)
• Corresponding physical units
• Rules for their application in equations

This standard facilitates clear communication among manufacturers, infrastructure managers, testing laboratories, certification bodies, and researchers working on high-speed rail, conventional rail, crosswind effects, tunnel aerodynamics, airflow, pressure waves, and aerodynamic loads by standardizing the representation.

It does not include specific limit values, test procedures, or performance requirements; these are addressed in other sections of this standard.

Engineers and researchers refer to this standard in the following situations:

• When writing simulation code (computational fluid dynamics)
• When reporting wind tunnel or runway test results
• When preparing technical specifications or tender documents
• Verifying compliance with aerodynamic technical interoperability specifications requirements.
• The standard “EN 14067-2 Part 2: Aerodynamics on an Open Track” defines physical phenomena specific to railway aerodynamics and provides recommendations for documenting tests. Locomotive manufacturers need to know the drag coefficient of trains to fit optimum power into their locomotives. Railway companies also need this to calculate their timetables and energy requirements, determine the type or number of locomotives needed for a particular train set, and assist in equipment purchasing decisions.

While train drag is normally the primary component of drag, it's difficult to isolate it from other components, so non-aerodynamic terms must also be considered in this section.

Motion resistance is expressed by a standard formula applicable to all train types. Furthermore, the measurement methods used to obtain a train's motion resistance, leading to a corresponding formula, are defined and described in a separate document (WI 00256127).

The EN 14067-2 standard covers the following:

• High-speed and conventional trains
• Certification and evaluation of railway vehicles.
• Infrastructure managers and railway officials
• Potentially lighter vehicles (trams, subways) in relevant situations

The main aerodynamic effects considered in open tracks are as follows:

• Head pressure surge (a temporary change in pressure felt when two trains overtake each other or when a train passes a switch at the side of the tracks)
• Runoff (a high-speed airflow that forms around and behind a moving train, posing a risk to trackside workers or light objects)
• Features of wakefulness flow
• Pressure changes affecting passengers (for example, when windows are open or during door operations)
• Aerodynamic forces acting on structures, people, or loose objects near the tracks.

This standard describes how these effects result from the train's speed, shape (nose/tail design), surface roughness, underbody geometry, and crosswinds.

• The standard “EN 14067-3 Part 3: Aerodynamics in Tunnels” defines the physical phenomena specific to railway aerodynamics and provides recommendations for documenting tests. This standard offers a descriptive overview of the fundamental physical phenomena specific to railway aerodynamics when trains enter, pass through, or exit tunnels. It highlights the unique closed-flow conditions in tunnels compared to open tracks.
• This standard is primarily informative. It does not define binding limit values, acceptance criteria, or detailed test and evaluation procedures. Instead, it describes aerodynamics and offers recommendations for documenting tests and measurements. The main aerodynamic phenomena addressed in tunnels are:
• Pressure waves: These are compression and rarefaction waves created as the train enters and exits the tunnel, and they propagate at speeds close to the speed of sound.
• Micropressure wave or micropressure pulse at tunnel exit: This is the sudden release of compressed air, creating audible explosive effects.
• Temporary pressure changes inside the train: These affect passenger comfort, especially ear discomfort, particularly when windows and doors are open or pressure insulation is inadequate.
• Piston effect: The air displaced by the train acts like a piston, creating a longitudinal airflow in the tunnel.
• Increased aerodynamic drag due to restricted flow.
• Pressure differences between tunnel entrances and along the length of the train.
• Impacts on tunnel infrastructure: For example, loads on tunnel lining, ventilation systems, or roadside equipment.

This standard explains how these effects depend on the following factors:

• Train speed.
• Train congestion ratio (train cross-section / tunnel cross-section).
• Tunnel length and geometry (single-track or double-track, entry type, shaft connections).
• Train front and rear design and surface sealing.
• Train length and crossing configurations (encountering trains in double-track tunnels).
• The standard “EN 14067-4 Part 4: Requirements and evaluation procedures for aerodynamics on open tracks” describes the requirements, test procedures, evaluation methods, and acceptance criteria for railway vehicles operating on open tracks. It provides requirements and evaluation methods for pressure variations and wind flow effects along the track. Evaluation methods for operational strength are addressed in this standard. Load conditions on infrastructure components caused by train-induced pressure variations and wind flow effects are also discussed. Test setups for ballast bulge evaluation are proposed for ballasted tracks.

The requirements apply only to heavy rail system vehicles with a maximum train speed exceeding 160 km/h and not to other rail systems. This standard applies to all open track rail vehicles and infrastructure with a nominal track gauge between 1435 mm and 1668 mm.

Train-induced aerodynamic effects can have the following impacts:

• Trackside workers and passengers on platforms (airflow velocities).
• Roadside objects and lightweight structures (e.g., loose debris, signposts, light shelters).
• Fixed infrastructure along the track (e.g., noise barriers, overhead track equipment supports, platform edges).
• Pressure transitions (head pressure stroke that occurs when trains pass each other or fixed points).
• Aerodynamic loads on structures and people near the rail.

This standard applies to:

• High-speed trains (typically at least 200 km/h, where aerodynamics are paramount).
• Traditional passenger and freight trains.
• New vehicle designs, modifications, or type approvals.
• Infrastructure compliance assessments.

This standard is compliant with the technical interoperability specifications requirements for high-speed and conventional rail in the EU.

• The standard “EN 14067-5 Part 5: Requirements and evaluation procedures for aerodynamics in tunnels” describes the aerodynamic requirements, test procedures, evaluation methods, and acceptance criteria for railway vehicles operating in tunnels. Aerodynamic pressure variations, loads, micro-pressure wave formation, and other aerodynamic considerations expected in tunnel operation are addressed in this standard. Requirements for the aerodynamic design of railway vehicles and tunnels for heavy rail systems are provided. These requirements apply only to heavy rail systems.

This standard ensures the safe and comfortable operation of railway vehicles in tunnel environments by controlling aerodynamic effects resulting from narrow geometries. It focuses on tunnel-specific phenomena and their effects on the following:

• Passenger and crew comfort (auditory discomfort due to pressure changes, ear blockage).
• The structural integrity and watertightness of the train (pressure loads on the wagon body, windows, and doors).
• Tunnel infrastructure (lining, ventilation, fixed equipment, loads on underground stations).
• Roadside workers and maintenance personnel inside the tunnels.
• Environmental influences outside the tunnel (e.g., micro-pressure waves or sonic booms at the entrances).
• Compatibility in situations where high-speed trains share tunnels with conventional traffic.

This standard applies to:

• High-speed rail (where the effects are most severe).
• Traditional railway in long tunnels.
• New designs, modifications, type approvals, and route compliance checks.
• Compliance with EU technical interoperability specifications for high-speed and conventional rail systems.
• The standard “EN 14067-6 Part 6: Requirements and test procedures for lateral wind assessment” describes the guidelines for lateral wind assessment of railways. This standard applies to all passenger cars, locomotives and power cars (with a maximum train speed between 140 km/h and 360 km/h) and freight cars (with a maximum train speed between 80 km/h and 160 km/h) and track gauges between 1435 mm and 1668 mm. For passenger cars, locomotives and power cars with a maximum train speed between 250 km/h and 360 km/h, demonstrating lateral wind stability is required. This standard does not apply to light rail and urban rail vehicles.

This standard focuses on the following:

• Aerodynamic forces and moments caused by oblique winds (crosswinds, yaw angles).
• Risk of tipping over (wheels losing control, leeward wheels lifting).
• Derailment due to excessive lateral forces.
• Compatibility with infrastructure (rail exposure categories, wind-prone sections).

This standard applies to:

• All passenger vehicles, locomotives, power cars, and multiple units.
• High-speed trains, conventional passenger trains, and, in relevant cases, certain freight vehicles.
• New designs, modifications, type approvals, and route-specific assessments.
• Compliance with technical interoperability specifications for high-speed and conventional railways in the EU.

This standard covers vehicles operating on open tracks (excluding tunnels, bridges or sheltered sections in some cases, unless otherwise specified).

• The standard “EN 14067-7 Part 7: Fundamentals of train-sourced ballast launch test procedures” addresses the following topics:
• Economic aspects of ballast projection.
• A comparison of methods used in France and Spain for railway vehicles.
• Infrastructure assessment methods.
• Review of the existing literature.
• Next steps and recommendations regarding standardization and research.

This standard provides informative guidance and basic information for the development, execution, and interpretation of test procedures related to train-induced ballast blasting. It does not define binding limit values, acceptance criteria, or mandatory test methods.

In short, the objectives of this standard are as follows:

• To harmonize understanding and approaches across Europe.
• To support consistent evaluation of railway vehicles and infrastructure.
• To facilitate the comparison of test results obtained from different methods/countries.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services in accordance with the EN 14067 standard.