In this paper, we propose an optimization model for determining locations of railway stations. The objective is to maximize the covered the number of expected passengers that can be covered. We focus on the case study of locating optimal stations of high speed train on the north route railway line of Thailand, which is on the government plan to be built. We considered the number of expected passengers based on the real passengers traveling during year on the line. Two types of coverage are considered, which are the condition on time to go to a station and the condition on total travelling time. To solve this problem, we developed Simulated Annealing. Computational results showed that the proposed metaheuristic algorithm found the high quality solutions in reasonable time.