Methods of Providing Hardware Safety for Microprocessor Train Control Systems

The hardware safety of train control systems is ensured by structural redundancy introduction techniques. Three main functional designs are considered—a duplicated structure, a triplex majority structure, and a self-checking redundant structure. The failure detection procedure is executed using a control element synthesized on Zhegalkin’s basis (elements AND, OR, and Exclusive OR), which allows using elements with unilateral failures for excluding dangerous situations. The triplex majority structure allows defining a point of failure to the accuracy of the controlled set, as well as the failure of the respective operation channel. The probability of a potentially dangerous situations is estimated for each considered structure, and the techniques used are compared on the basis of an introduced specific efficiency factor. If we use this criteria, taking into cost, reliability, and safety into account, it will turn out that the best characteristics are found in the duplicated structure.