Currently, certification against EN standards on railway dynamics in particular, together with the relevant technical annexes of the Technical specifications for interoperability (TSI) following various tests methods, extend train delivery times for months. Additionally, the tests do not always capture all operating conditions; there is thus a risk of failure or unsafe approximation in such tests.

Some uncontrolled environmental and other boundary test conditions combined with restrictive operational limits can also influence results. The costs and duration of tests performed in such conditions are also often increased by the need to do these tests several times so as to explore as much as possible all the range of environmental and boundary conditions and secure the results.

Simulating of the dynamic behavior of rail vehicles could enable the following, the project organizers said:

• It is envisaged, through further validation of their prediction capacity within this project, to use multi-body vehicle models for the certification of a vehicle, once submitted to a first series of tests, to extrapolate the tests results to other conditions, as required for certification. For the cases in which the latter conditions would have been difficult to meet, if the running test were actually to be organized, time and money can be saved in the vehicle certification process;

• It is also envisaged to use the simulated behavior of a new or modified vehicle “close” to a vehicle already certified by test, to avoid repeating certification tests on the new or modified vehicle.

The more specific objectives of DynoTRAIN are to:

• address high-speed and convent rail (HS & CR) TSIs that effectively work to harmonise European and national standards on railway dynamics and track interaction to reduce costs and time of certification;

• reduce costs and time of certification by replacing existing tests;

• reduce costs of certification by introducing virtual testing;

• close open points in the HS and CR TSIs; and

• establish standardized conditions for derivation of results.

DynoTRAIN gathered 22 partners from 7 European countries and is coordinated by UNIFE, the European rail industry. Major European railway operators, rolling stock manufacturers, universities and research centres worked on the project.

The Work Program was organized around 6 technical Work Packages:

1. Measurements of track geometry quality and virtual homologation;

2. Track geometry quality;

3. Contact geometry;

4. Track loading limits related to network access;

5. Model building and validation;

6. Virtual certification of modified vehicles and vehicles running in other conditions.

WP 7 is a quality assurance work package—transverse to the others—that aims at ensuring the acceptance of the results of the project by European and National Safety Authorities.

Dr. Yann Bezin, Head of Research at the Institute for Railway Research (IRR), University of Huddersfield (UK), one of the DynoTRAIN partners, explained:

Before you are allowed to run a vehicle in a country you need to make sure it is safe and that implies a lot of physical testing. So you build a prototype of the train and it is tested through an intensive and long programme of physical testing.

If you build a fleet of vehicles to sell, the cost of a full train would be spent on certification. That is quite a large proportion, because you don’t sell hundreds of trains.

A speciality of the IRR is in the development of modeling software that can simulate the dynamic behavior of railway vehicles, leading to estimate the safe operation of a train in differing conditions. One of IRR’s tasks in DynoTRAIN was to build mathematical tools that take data collected from different countries about the track and synthesize that data into a representative track that could be used in a virtual test environment, Dr. Bezin said.

Manufacturers would be able to use virtual test tracks to make adjustments to vehicles according to the conditions in which they would be used. It is hoped that the findings of DynoTRAIN, including the IRR’s contribution, will help to establish virtual testing as a valid route to certification.

Instrumented wheelset for measurement. Source: TrioTRAIN. Click to enlarge.

DynoTRAIN relies on a massive database of information about real tracks and real railway systems and this was gathered as part of DynoTRAIN by assembling a special train—locomotives, passenger carriages and freight wagons—fitted out with a battery of testing equipment, such as a laser system that captured the shape of the rail every 25 cm over thousands of kilometers.

‌This train ran in Germany, France, Italy and Switzerland, capturing the characteristics of different tracks in different countries, including high speed lines and slower, local services. This furnished a huge amount of data that could be used in order to help validate vehicle models and build virtual test tracks.