Train operation is suspended to ensure safety when the precipitation observed by a rain gauge exceeds the train operation control criteria. This paper proposes a method to determine the rain gauge installation interval and the train operation control criteria suitable for hourly precipitation. Those are evaluated from the viewpoints of both safety and reliability of train operation, based on the spatial distribution of precipitation observed by rain gauges. This paper shows the combinations of the rain gauge installation interval and the train operation control criteria which can improve either safety or reliability when one is kept constant, or can improve both. For instance, in the case that the rain gauge installation interval is reduced from 10 km, which is the current standard interval adopted by many railway companies, to 5km, the train operation control criteria are raised by 17% and reliability can improve by 25% when safety is kept constant, and the train operation control criteria are raised by 8% and safety can improve by 19% when reliability is kept constant.
