Chapter 153
Modeling of Train Control Systems Using
Formal Techniques
Bingqing Xu and Lichen Zhang
Abstract Train control systems must guarantee a very high level of safety because
their incorrect functioning may have very serious consequences such as loss of
human life, large-scale environmental damages, or considerable economical pen-
alties. The software reliability is related to several factors, such as completeness,
consistency, and lack of ambiguity. Formal methods are widely recognized as fault
avoidance techniques that can increase dependability by removing errors during the
specification of requirements and during the design stages of development. In this
chapter, a brief overview of existing results on formal specification of train control
systems is first presented. Then we propose an integrated formal approach to
specify train control systems; this integrated approach combines CSP and Object-
Z with Clock theory to specify the Railway Control System concerning both the
linear track and crossing area, especially the time delay between any two aspec ts of
the railway system.
153.1 Introduction
Train control systems must guarante e a very high level of safety because their
incorrect functioning may have very serious consequences such as loss of human
life, large-scale environmental damages, or considerable economical penalties
[1]. To meet safety and reliability requirements, the relative international standards
recommend the application of formal methods in specifying development specifi-
cations and design for train control systems, the approaches using formal methods
which can eliminate ambiguities of specification, and specify and prove system
specification in a rigorous mathematical way, were highly recommended for the
railway systems which belong to software safety integrity level 4 [2]. Although the
B. Xu • L. Zhang (*)
Shanghai Key Laboratory of Trustworthy Computing, East China Normal University,
Shanghai 200062, China
e-mail: zhanglichen1962@163.com
W.E. Wong and T. Zhu (eds.), Computer Engineering and Networking, Lecture Notes
in Electrical Engineering 277, DOI 10.1007/978-3-319-01766-2_153,
© Springer International Publishing Switzerland 2014
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