Compulsory ticket areas (CTA) do not correlate 1:1 with Penalty Fare areas/stations. The former are not used much at all on National Rail stations, compared to the latter.Presumably a "compulsory ticket area" is part of the Penalty Fares schemes / areas - in other words, under normal circumstances (ie assuming the technology is functioning) - it is an area (platform / train or similar) where you are not permitted to be unless you have a ticket and it is (in theory at least) your responsibility to make sure you have one. Contrast this with a line with unstaffed stations with no ticket machines (particularly pre-internet) - you are perfectly entitled to be on a platform / train with no ticket, because you have never been given the opportunity to purchase one. The logic breaks down somewhat where the ticket machine is inside the "penalty fares area" - meaning that you have to enter the "penalty fares area" without a ticket in order to purchase one!
why is a ticket required in a non compulsory ticket area. ? If a ticket is required it should be in a compulsory ticket area
Compulsory ticket areas (CTA) do not correlate 1:1 with Penalty Fare areas/stations. The former are not used much at all on National Rail stations, compared to the latter.
TfL stations, eg Overground, form a significant number of the extant CTAs.
This is all sounding like something from "Yes, Minister"...