In the case of Seoul Metropolitan Area Railway Tunnel, most of the task section is composed in the tunnel. Unlike Ho-nam HSR line and Gyeong-bu HSR Line. Therefore, the effect of cross wind can be neglected in determing the track-center distance.
In this case, by eliminating the effect of the cross-wind, track-center distance of the existing railway design Criteria can be reduced from 4.8m to 4.5m and the optimal cross section to meet the interference conditions and groove joint construction gauge, train lines in the tunnel.
For the reduced tunnel section of Seoul Metropolitan Area Railway, all specification criteria of such as a ringing in the ears and micropressure required for high speed train were found to be satisfied from the theoretical analysis.