In this study, for the rapid transit of urban and metropolitan railways, the installation of passing loop tunnel in the underground section of urban railroads in operation is reviewed. Unlike road tunnels, it is difficult to secure working spaces because the railwau tunnel is very narrow, impossible to bypass, and related facilities such as overhead wire exist. In addition, urban railways have limitations that must be carried out without blocking the existing trains or construction within four hours when the trains are not running. Therefore, in this study, the construction plan of passing loop tunnel during railway operation for the rapid transit was reviewed.