The focus of this paper is on reducing the complexity in
verification by exploiting modularity at various levels:
in specification, in verification, and structurally.
\item For specifications, we use the modular language CSP-OZ-DC,
which allows us to decouple verification tasks concerning
data from those concerning durations.
\item At the verification level, we exploit modularity in
theorem proving for rich data structures and use this for
\item At the structural level, we analyze possibilities
for modular verification of systems consisting of various
components which interact.
We illustrate these ideas by automatically verifying safety
properties of a case study from the European Train Control
System standard, which extends previous examples by comprising a
complex track topology with lists of track segments and trains
with different routes.