Simulating the Oslo Subway by Hierarchic Coloured, Object-oriented timed Petri Nets with viewpoints

In this paper we discuss some difficulties in modelling
and extracting relevant information from large concurrent
systems. We present the concept of 'viewpoint', how one
can observe high level behaviour from low level behaviour
of Petri Nets. The fruitfulness of viewpoints in simulating
and monitoring real railway systems is demonstrated, by
an experimental Petri Net tool, called Andromeda, supporting
hierarchical, coloured, object-oriented, timed Petri Nets,
with viewpoints. The Oslo Subway is modelled as a large
modular coloured Petri Net, using all Andromeda's features.
To test our approach, large scale simulations of the subway
traffic have been performed.