Transport Research and Innovation Portal

Background & policy context

The current interoperability approval process for new High Speed and Conventional railway vehicles in Europe is a very long and costly process. The European Railway Agency (ERA) is charged with the development of new and future Technical Specifications for Interoperability (TSIs), which provide common regulations for the authorisation of the placing into service of new vehicles. TSIs will provide a safe and technically-compatible railway system for Europe by specifying requirements for all relevant technical aspects. However, they will not directly eliminate the burdens that currently affect the railway industry and the railway undertakings regarding new vehicle approval on each national network in Europe.

TSIs are a set of common minimum requirements and therefore not optimal for every network administrator and/or railway undertaking. Placing in service a new vehicle, even if compliant with TSIs, still requires network approval by each National Safety Authority(NSA) responsible for the Member State in which the vehicle is to be operated.

In addition to the handicaps mentioned above, it is important to take into account the lack of compatibility of the national assessment methods. Therefore it is often requested by the Member States to repeat specific tests for homologation that are analogous to those tests already performed in other countries. At present a full harmonisation of the assessment methods required does not exist, although the evolution of new and expanded European standards is helping to close the gap.

AeroTrain will help meet the business scenarios listed in the ERRAC (SRRA 2002 and 2007) by aiding the spread of European homologation and acceptance procedures to speed up interoperable product approvals while squeezing out risk through improved safety management. In the field of aerodynamics a recent European standard (EN) focuses on common definitions and descriptions of the aerodynamic phenomena and measurement procedures. Due to its application for all types of rail traffic it has not converged yet to one method per phenomenon but allows variations arising from national rules. The focus of the project is therefore on using the TSI route to consolidate the methodologies allowing the free exchange of certification data.

The network approval of multi-system vehicles is a key subject that can and must be addressed in order to provide a competitive railway system within Europe. Therefore, the importance of AeroTRAIN, as it will contribute to the practical implementation of interoperability across Europe by leading to a faster, cheaper and better certification and authorisation process for all involved stakeholders.

The AeroTrain project is part of the TRIO-TRAIN cluster (Total Regulatory Acceptance for the Interoperable Network) which comprises three related projects dealing with key railway interoperability issues: Aerodynamics (AeroTRAIN), Railway Dynamics and Track Interaction (DynoTrain) and Pantograph/Catenary Interaction (PantoTrain) all submitted under the 2^nd Call of FP7.

Objectives

The overall goal of the project AEROTRAIN is to promote interoperable rail traffic in Europe by reducing costs and time of certification and closing "open points" in the TSI's. It will be achieved by the following high-level objectives:

1. address HS & CR TSI's that effectively work to harmonise European and national standards on aerodynamics to reduce costs and time of certification;
2. reduce costs and time of certification by replacing existing cross wind and slipstream tests with new alternatives without reducing safety;
3. reduce costs of certification by introducing virtual testing as far as it can be validated for head pressure pulse loads and crosswind aerodynamic loads. This will allow in the long term the use of more controlled environmental testing conditions which will increase safety and enable more realistic conditions for crosswind safety assessment to be investigated, reducing uncertainty and thereby avoiding unnecessary and costly infrastructure measures. For crosswind it includes both more realistic wind scenarios as well as more realistic modelling of the train on different infrastructure as embankments and viaducts;
4. close "open points" in the HS and CRTSI's. Derive limit values and where necessary newcertification procedures. Introduction of limits for aerodynamic loads on the ballast track will have the added effect of ensuring that the higher-speed trains for the future will be more streamlined with regard to the under-floor regions, which will promote more energy-efficient trains.

Technical objectives and expected results:

• Slip stream effects: replace two test procedures with one at a test site that is easily accessible in all countries. From this will be derived:
1. transfer functions from the ballasted straight track conditions to that of a platform;
2. a specification of a new test procedure for TSI;
3. the influence of single vehicles in a train to support CR TSI.
• Crosswinds: Aiming at the certification of vehicle resistance to overturning in strong winds, the objectives and results are the following:
1. Replace the current wind tunnel evaluation configurations of a train on a 6m embankment or flat ground with the prEN14067-6:2009 agreed configuration using ballast and rails for the certification of HS and CR vehicles according to the TSIs. Measure aerodynamic coefficients and apply vehicle dynamic simulations to compute limiting wind curves for most sensitive CR vehicles with proven safe operation, and reference HS vehicles to derive limiting values for TSI;
2. Determine the application range of standard and more advanced CFD simulation methods for assessing the aerodynamic loads;
3. Develop and validate procedure for virtual testing of aerodynamic cross wind loads;
4. Assess the transformation function to derive the aerodynamic load from ballast and rail configuration to embankment configurations for national treatment of cross wind safety by Infrastructure Managers;
5. Determine the influence of train movement on the aerodynamic loads when on an embankment. This will be a first step to reduce conservatism in the assessment of cross wind safety.
• Open air pressure pulses:
1. collect a database of measured pressures pulses from various trains;
2. verify that the maximum pressure load is associated with the passing of the train head;
3. verify numerical simulations procedure with measurements for virtual testing.
• Aerodynamic loads on track:
1. standard specification for a measurement technique which captures the basic parameters of the ballast pick-up phenomenon;
2. standard track on which trains should be tested;
3. standard post processing procedure for the measured data;
4. formulation of a TSI certification criterion.
• Train-tunnel interaction:
1. definition of a simple standard tunnel geometry which will form the reference scenario for future train assessment with respect to micro-pressure wave characteristics;
2. CFD-investigation of existing European high-speed trains;
3. proposal for a generic benchmark train which will set the criterion for permissible pressure gradients;
4. reduced model-scale tests on entry pressure gradient to verify CFD results;
5. proposal for limiting criterion for train assessment with respect to TSI and EN.
• Quality Assurance & Regulatory Acceptance:
1. to assess scientifically the uncertainties in current and new procedures to ensure that the safety level is maintained or improved. The Project will identify and quantify the main contributors to the overall uncertainty which can be used to focus the work where it is most efficient;
2. to validate the applicability and promote future uptake of the proposed certification procedures and limits by communication with ERA, CEN and National Safety Authorities (NSA's);
3. to arrive at a convincing proposal for standards. The proposals have to be of such quality so as to convince all interested stakeholders, starting from those participating in the project, of the safety, effectiveness, efficiency and feasibility of the proposed certification process.

Methodology

On the basis of the requirements for the new CR TSI and revision of HS TSI, opportunities to reduce certification costs and, where it is seen that virtual certification could be introduced, it is decided to focus the study on five main aspects of rolling stock aerodynamics that are or need to be subject to certification. Hence the Work Program of the project is organised around five technical Work Packages:

Open Air-Pressure Pulse:

• to develop a significant database about the open air pressure pulse by combining:
1. existing GB databases on air pressure pulse;
2. existing or future continental databases corresponding toTSI / EN requests.
• to contribute to this database by contributing in measuring – following TSI / EN requests and possible GB requests as well – various characteristic trains and locomotives;
• to test the currently available CFD methods in predicting the open air-pressure pulse by refined comparison with the prepared full-scale databases. Both streamlined and un-streamlined trains, as well as locomotives and coaches, are to be simulated;
• to identify potential limitations of the various CFD approaches and prescribe validation processes for the methods and the tools;
• to provide proven methods to successfully compare CFD results with the TSI limit;
• to provide a CFD approach to certify a rolling stock derived from an already certified train;
• to develop a clear text to be used as a new input within CEN and/or TSI texts.

Aerodynamic Loads on Tracks - to define and agree on:

• a standard specification for a measurement technique which captures the basic parameters of the ballast pick-up phenomenon;
• a standard track on which trains should be tested;a standard post-processing procedure for the measured data;
• a formulation of a needed TSI certification criterion.

Crosswind:

• to close a TSI open point by delivering a limit criteria for crosswinds (Reference Characteristic Wind Curves) to CR RSTTSI and for Class 2 trains of HS RST TSI on the prEN14067-6:2009 single track with ballast and rails standard configuration;
• to derive Reference Characteristic Wind Curves and limit criteria for class 1 trains of HS RST TSI on the prEN14067-6:2009 single track with ballast and rails standard configuration. This would lead to a reduction in the costs of certification by considering, instead of the data from the existing two ground configurations in HS RST TSI, the data obtained for the single track with ballast and rails configuration, in combination with a transformation from single track with ballast and rails configuration to current TSI configurations;
• to validate virtual certification by proving that CFD investigations are suitable to faster time-to-market with respect to rolling stock conformity assessment;
• to assess the limits of experimental simulation of reference ground configurations, and establish the methodology for considering aerodynamic loads on embankments.

Train - Tunnel Interaction:

• close an open issue within EN / CR TSI regarding pressure loads on CR RST running in tunnels. Therefore, information on existing lines, tunnels and CR trains shall be gathered to identify characteristic aerodynamic loads in tunnels. Next, extensive simulations are performed to obtain pressure loads and to assess their frequency of occurrence. A proposal for dimensioning guidelines for CR RST with respect to aerodynamic loads in tunnels will be derived;
• set up a TSI criterion regarding micro-pressure waves (MPW) for interoperable trains to limit MPW effects in tunnels. Through the vast work by the Japanese in publications and through personal exchange the essential understanding of the phenomena exists which allows the work to focus on the train entry-pressure gradient to achieve a limit suitable for European conditions. Therefore, the process how to derive the pressure gradient and the threshold value for this gradient are assessed in the task. A limiting criterion will be submitted.

Slip Stream Effects:

• to undertake a variety of slipstream measurements at different heights above the TOR for ballasted straight track. These measurements will be undertaken on both High-Speed Trains and conventional trains;
• to repeat the measurements outlined above on a platform at a variety of heights;
• to integrate existing data with those proposed above in order to extend the measurement database and ensure compatibility across a wide range of European railway conditions;
• to analyse and process the results outlined above.

Dissemination and ensuring the acceptance of the results of the project by European and National Safety Authorities. Methodologies will be defined to be applied to all the procedures developed in the other WPs in order to check and guaranty the quality of the results and propositions.

Research Programme

FP7-SST - Sustainable Surface Transport

Leading institution(s)

Public institution:

European Commission

Type of funding

Public (EU)

Funding Source

DG RTD

Key results

The project will bring a procedure for virtual certification of head pressure pulse valid for streamlined and non-streamlined trains, including the applicability of inviscid panel methods, and a verification that the maximum peak-to-peak pressure change occurs at the head of the train.

AeroTRAIN will establish common vehicle requirements to derive dimensioning guidelines for CR RST with respect to aerodynamic loads in tunnels, and set up a TSI criterion regarding micro-pressure waves (MPW) for interoperable trains to limit MPW effects in tunnels

Expected results on slip stream effects are the development of a transfer function which will enable measurements made at one location (e.g. at the trackside) to be related to those at a different location (e.g. on the platform); and a reduction in the technical requirements concerning the evaluation of slipstream velocities and hence an increase in the integration of rail transport activities across the EU.

The AeroTRAIN project will introduce:

• Limit Characteristic Wind Curves for Conventional Rail TSI and Class 2 High Speed trains;
• Limit Characteristic Wind Curves for Class 1 High Speed trains based on reference trains;
• Range of application of CFD methods and the corresponding procedure for assessment of crosswind aerodynamic load;
• An appropriate test procedure for crosswind aerodynamic load with more realistic conditions (train movement and embankment) and limitations of CFD methods for the corresponding configuration.

Innovative aspects

The main innovation brought by AeroTRAIN with regards to aerodynamic loads on tracks are the following:

• A measurement technique to assess the aerodynamic load in relation to the risk of ballast pick-up;
• A measurement of the aerodynamic load on track by different high speed trains with a common measurement procedure;
• A robust measurement and post processing procedure which captures the basic parameters of the ballast pick-up phenomenon suitable for certification;
• A standard track conditions to measure on;
• A limit criterion for TSI.

Input in EU Transport White Paper 2011 targets

Innovating for the future: A European Transport Research and Innovation Policy

Partners

Belgium:
Union des Industries Ferroviaires Europeennes (UNIFE) (Coordinator)

France:
Alstom Transport S.A.; Alma Consulting Group SAS; Union Internationale des Chemins de Fer (UIC); Société Nationale des Chemins de Fer Francais (SNCF); Université de Valenciennes et du Hainaut-Cambresis

Germany:
Bombardier Transportation GmBH; Deutsche Bahn AG; Technische Universität Berlin; Siemans AG

Italy:
Universita degli Studi di Roma la Sapienza; Ansaldobreda S.P.A.

Spain:
Tecnologia e Investigacion Ferroviaria SA; Administrador de Infraestructuras Ferroviarias; Construcciones y Auxiliar de Ferrocarriles Investigación y Desarrollo, S.L.; Renfe Operadora

United Kingdom:
Rail Safety and Standards Board Ltd.; University of Birmingham.

Contact for further information

COUTURIER, Martin (Mr)
Union des Industries Ferroviaires Europeennes (UNIFE)
Avenue Louise
BELGIUM

Tel: (+32) 02 642 23 21
Fax: (+32) 02 626 12 61

CORDIS: Project page
Website: Organisation website
Website: AEROTRAIN Project website