block system

English

Noun

block system (plural block systems)

1. (rail transport) On railways, a system by which the track is divided into sections of three or four miles, and trains are run by the guidance of electric signals so that no train enters a section or block before the preceding train has left it.
   • 2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, →ISBN, page 41:

     Signalling was by the standard 'block' system of the time, which prevents any two trains being on the same track section at once, but this was operated with boldness, with margins shaved. The Metropolitan would prove to have an excellent safety record nonetheless.

2. (mathematics) Given a group G that acts on a set X, a partition of X that is G-invariant.

References

• “block system”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.