Safety evaluation of a train leader telephone system

Abstract

The paper describes methods used in a safety evaluation of a train leader telephone system. These methods include Fault Tree Analysis of the system in its environment to identify possible hazards, HazOp analysis based on the user interface, to identify faulty operator information which can cause these hazards, and FMECA based on Message Sequence Charts to identify possible computer failures which can lead to this faulty information. Emphasis is put on drawing conclusions on the general applicability of these methods.