In contemporary railway traffic, different train services often run on the
same track of a railway section. Since these train services generally trave
l at different speed, this may result in delays due to fast trains being ca
ught behind slower ones. This note investigates these delays developing a s
tochastic model capturing both scheduled and unscheduled train movements. R
unning time distributions for each train service can be obtained solving a
system of linear differential equations. This system can be solved explicit
ly when free running times for all train services are deterministic. The ma
thematical model falls in the class of infinite server resequencing queues,
and the results generalise existing results for such queues, allowing depe
ndence between consecutive interarrival times, as well as between interarri
val times and service times. A case study of a railway section in the Dutch
railway network illustrates the practical value of the model, both for lon
g and short term railway planning. (C) 2001 Elsevier Science Ltd. All right
s reserved.