A section of double railroad tracks formed by the temporary convergence of two parallel tracks in such a way that each set remains independent while traversing the same ground, affording passage at a narrow place without need of switching.

• 套式铁轨一段铁路轨道，其中两股道由于两条平行轨道暂时会聚而重叠，并使得每一股轨道都各有一根钢轨位于另一股轨道的两根钢轨之间，使得在狭窄的地方不需要换轨