Regulations and corporate manuals on railways are regarded in a broad sense as a software to specify the operation of man-machine system in railways. Although it is not an easy task, the reliability and safety of manuals shall be validated　when a provision has been changed as necessity arises against technological innovation and social changes. This paper proposes a technique to evaluate the reliability and safety function of manuals by documentation of logical relation and decision process to use the technique of requirement definition in software engineering, and introduces an operation tool to use a computer for the above purpose.

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