The bottleneck of ESB railway line is the single track line from Chachoengsao to Si Racha (see Fig.1). The “ruling” longest transit time for station-to-station in Chachoengsao to Si Racha section is 19.33 minutes. Applying the usual SRT signaling and safe working time for reoccupation of 3 minutes, the line capacity can be calculated as follow [13]: