Although the effectiveness of an express train"s service is measured in "Total System Time or Cost" units, many cases had used indirect method what based on the distintion by number of passengers in a station or experiential knowledgements. These methods are not guarantee itself as an optimal strategy. Focusing "Total System Time or Cost" directly, this paper investigates the express train service"s stop scheduling based on each OD-volume and trip time which mainly affect system time and cost. To do this, we built an IP model which has a binary set presenting express train"s stop scheduling as decision variable and suggest a Genetic Algorithm (GA) to find heuristic optimal solution.