Abstract: A rail-arrangement having a first mounting rail and a spaced apart second mounting rail for receiving carrier units for fibre-optic components, in particular for patch panels. The first and second mounting rails each extend over multiple discrete height levels (H1, H2, H3), to receive and to distribute the received carrier units. Each mounting rail has at least one primary linear guide at each height level (H1, H2, H3), to guide the received carrier unit parallel to a longitudinal axis (L) of the mounting rail. Each mounting rail has, at at leas one height level (H1, H2, H3), bearing surfaces for the primary linear guide and/or for the received carrier unit. The bearing surfaces are spaced apart from one another along the longitudinal axis (L) of the mounting rails.