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Assessment of vehicle-track interaction with special reference to DYnamic SAFety in operating conditions


Objectives and content
Train and Track dynamic interaction is a key issue of
Railways operation. The forces generated at the
interface between wheel and rail determine the conditions
of a safe operation of trains, with regard especially to
derailment and track resistance, and of a good ride
quality, i.e. a high level of comfort.
Safety criteria and limits are defined, allowing to
guarantee that no dangerous conditions can be met in
operation conditions. Three dynamic safety criteria are
at stake: the derailment, the track lateral resistance
and the overturning conditions. But these limits are
based on the results of scientific investigation
performed in the early 70s, mainly at low speed, and the
dynamic interaction effects are not well enough
understood and quantified with regard to the present
requirements of railways. The increase of commercial
speed, the development of technologies aimed at fully
exploiting the capacity of the railways system, such as
tilting trains, indeed require a better understanding of
this interaction, with consideration of the whole range
of dynamic efforts at stake in safety and comfort. As
the safety margin included in criteria is not known very
accurately, it is probably often larger than really
necessary, and is a limiting factor, hindering the full
exploitation of the infrastructure.
There also exists a lack in measurement techniques to
characterise the dynamic interaction between a vehicle
and the infrastructure. Such techniques are of course
available to investigate the behaviour of prototypes, but
they are difficult to use and costly. In front of the
requirements of vehicle development and certification,
and of interoperability rules, these techniques are far
from being efficient and cost-effective enough.
DYSAF intends to bring a decisive progress in these two
fields, and thus to open new possibilities to railways.
The first objective of DYSAF is to investigate the
dynamic phenomena at stake in derailment and overturning
This will be made mainly thanks to an especially designed
test running gear, allowing full-scale and high-speed
experiments in extreme conditions. Thus the dynamic
effects at stake in derailment, wheel unloading, etc.
Will be well characterised. Parametric numerical
simulation will be performed in association with
experiments, to help determining the dynamic behaviour
laws. Both approaches will lead to establish much more
precise and validated criteria, but they are quite
innovative and a high level of risk is associated to this
The second objective of DYSAF, once these dynamic
interaction effects well understood, is to investigate
how the relevant parameters could be measured in practice
for certification, operation control and track
maintenance This will lead to propose functional and
performance specifications for an Integrated Dynamic
Monitoring System (IDMS) adapted to the needs of
railways, manufacturers, certification bodies in a range
of applications, from engineering of new techniques to
certification and control of interoperability conditions.
Advanced technologies capable of improving the track
inspection policy and reducing its costs will also be
investigated, as this is a major component of a global,
sustainable safety and quality policy.
The third and last objective of DYSAF is to establish a
very efficient exploitation policy, allowing to rapidly)
and widely exploit the scientific innovation in the
domain of dynamic interaction (definition of new
harmonised safety criteria and guidelines for the
definition of safety limits) and to support and encourage
the development of improved monitoring techniques.

Fields of science

Call for proposal

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European Rail Research Institute
EU contribution
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754,Arthur van Schendelstraat 754
3511 MK Utrecht

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Participants (12)