A symmetrical timetable is a timetable whose direction of travel is symmetrical with the return direction. This is accomplished by mirroring the timetable in time in a time-out diagram. The time chosen to mirror the timetable is called symmetry time. In a symmetrical timetable, it is true that at the symmetry time all vehicles cross their opposition.
The main reason for making a symmetrical timetable is to ensure that connections for the right direction also work for the return. For example, it is possible to travel from Amsterdam to Holten by moving to Deventer. The railways make sure that in Deventer the train to Holten is on the other side of the platform and leaves Amsterdam shortly after arriving at the train. The symmetry makes it possible to travel from Holten to Amsterdam with a short transfer in Deventer.
In the Netherlands, the symmetry time is in accordance with international agreement, .59 and .29. Originally in the Netherlands for .17 and .47 were chosen, only international trains were due to .00 / .30. With the introduction of the NS timetable 2007-2009, Dutch symmetry is aligned with abroad. Also see
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