Improved system modelling for better railway performance

Author: Arco Sierts
Day: Aspect Day Two
Session: Performance

It is commonly heard that the railway system is a complex
system.Complexity makes the total system and its behaviour
difficult to understand, especially for those who lack practical
operational knowledge and experience. As a consequence, there
is a serious risk that changes both inside and outside the system
lead to unexpected and unwanted results, such as delays, higher
costs, decreased performance and safety risks.According to the
authors, this is one of the principal reasons why innovation speed
in railways is slow, and the integrated railway system lacks
adequate resilience towards the transportation market. The
authors of this paper are therefore convinced that a better
understandable modelling of the railway system will contribute
strongly to an improved railway system performance.In 2010, Van
den Top published his thesis "Modelling Risk Control Measures in
Railways". In this thesis, which mainly focused on railway safety
modelling, the so-called 'cascade model' was presented. This
model was used to visualize the top-down system control chain,
starting on strategic level, and ending in the real-time operational
railway system. One of the fundamental conclusions was that the
railway system lacks adequate bottom-up-feedback that could
correct wrong assumptions of the higher level control structures.
This conclusion was also drawn in many other publications and
theses.In this paper we will present an improved version of the
cascade model: the railway control chain model. This model
shows in more detail the overall railway system control
fundamentals, without going into technical detailsthat are hard to
understand. As a practical added value, the model will be used to
analyse the difficulties with the implementation of ETCS in
Europe. The paper concludes with several improvement
possibilities for ETCS: from strategic political level to operational
policy and practical implementation.