In this paper, we review a variety of state-of-the-art research on assessment of the railway track capacity. We address the three well-known methods (Yamagishi, UIC 406, and TCRP-13) with individual case study in this research field. First, we explicitly present every derivation-step of the Yamagishi equations that has been most frequently applied in the Korean railway without clear understanding for it. Further, we present a prospective application scheme of the method as an analytic assessment method. Second, we address establishing process of UIC 406 standard and its application method, which is known as the standard method in Europe. Finally, we address the method and application of TCRP-13, and present comparison between the three methods. This paper is expected to contribute for improving understand on the in-using equations and methods in practice as well as for activating application of the internationally well-used method to the Korean railway.