During the period of rapid economic growth, Japan's large cities focused on economic development and rapidly developed their social infrastructures. As a result, the underground space of cities has become saturated with congested infrastructure such as highways, railroads, energy, communication and power grids, and social infrastructure such as water, sewage, electricity, and gas have been constructed in the shallow depths of underground space. An increasing number of existing subways in urban areas have been in service for 50 years. For example, The Tokyo Metro Co., LTD. started with the Ginza Line, which opened in 1927, followed by the Marunouchi Line, Hibiya Line and Tozai Line. Recently, large-scale reconstructions involving structural changes have been carried out in existing tunnels in response to the need to improve the functionality of facilities and other features in accordance with the times. The design standards of the subways that have been built have been streamlined and improved according to the times. The joints of subway structures that undergo major reconstruction are heavily structured because different verification methods are used. Therefore, it is necessary to examine the rationale for the performance evaluation method of the frame. This paper first analyzes the treatment of laws and ministerial ordinances pertaining to railroad projects. Then, the concept of past design methods is clarified and issues in the performance evaluation method of the frame are extracted. The effects of different performance assessment methods on the cross-sectional calculations of members are analyzed using one-layer, two-diameter and two-layer, three-diameter open-cut railway tunnels as examples. As a result, under the influence of the cross-sectional force calculation method, the bending moments in the upper and lower slabs are 40% larger when using the framework calculation method than when using the deflection angle method. The effect of the lateral earth pressure equation showed that the corner and central bending moments of the lower slab were larger when the lateral earth pressure coefficient was large and hydrostatic pressure was applied. In terms of the influence of the cross-sectional verification method, when the verification method using allowable stress is used, it is desirable to set the cross section not only for the rationality of the structural calculation but also to provide a margin of allowance. Although the current verification method considering the limit state has the existing member capacity, it may be difficult to ensure the partial safety factor in the design.