Passing loop

A similar arrangement is used on the gauntlet track of cable railways and funiculars, and in passing places on single-track roads.

A disadvantage of the platform and through arrangement is the speed limits through the turnouts at each end.In the example layout shown, trains take the left-hand track in their direction of running.

Overtaking is not normally possible at this kind of up-and-down loop as some of the necessary signals are absent.

An extra parallel siding is often built at stations on refuge sidings so that two stopping trains can pass, and an extended catch point opposite the refuge siding may be added so as not to interfere with passing trains.If a crossing loop is several times the length of the trains using it, and is suitably signalled, then trains proceeding in opposite directions can pass (cross) each other without having to stop or even slow down.

Since the available space for crossing loops is usually limited, they do not normally have an overlap (safety margin) between the starting signals and the end of the double line.

In Australia, the Australian Rail Track Corporation (ARTC) policy provides for overlaps of about 500 m and 200 m respectively in an effort to avoid derailment or collision.

A crossing loop on steep gradient may have catch points on the downhill end to reduce the impact of runaways.

Line capacity is partly determined by the distance between individual crossing loops.

The longest section between successive crossing loops will, like the weakest link in a chain, determine the overall line capacity.

Two long trains can cross at a short loop using a slow so-called see-saw process, which wastes time.