The study about applying concentric circle to curved line in railroad

복선철도에서 구축과 내$\cdot$외측 궤도의 동심원 선형구성의 필요성 연구

The curved line in construction of railroad is inevitable. Also it needs a transition curve when the straight line connects to curved line. In this research, by establishing the reciprocal relations of inner, center and outer track, we will present the calculation method of construction-center line in normal double-track railroad which uses cubic parabolic type as a transition curve.