Abstract
Railway signalling systems need high level of safety, and are also required to achieve higher availability. In the past, there were some analyses for effective measures from the viewpoint of the minimization of total costs. However, these analyses are the bottom up approach and are not from the view point of policies of measures, which are directions from the view point of frequencies and consequences of failures, required by systems for improving availability. Therefore, a strategic decision method of effective measures for the achievement of targeted availability is proposed. This method can consider failure frequencies per unit time and the duration of downtime of train operation at the same time, and by applying the proposed method to a railway line, it is shown that it can contribute to applying effective measures depending on kinds of failures and characters on the line.
