It can also get very station-specific. Using the Elizabeth line as an example:
Reading-Iver inclusive: same platforms as National Rail, same gatelines, pay-as-you-go available, not Oyster, but Freedom passes OK after 9:30.
Heathrow Terminals 2 & 3, 4, 5: separate gatelines for Piccadilly, shared platforms with National Rail, all tickets OK, but only Heathrow Express ones valid on HX trains.
Hayes & Harlington-West Ealing, Acton Main Line: shared platforms & gatelines with NR.
Ealing Broadway: shared gateline for all services, separate platforms for Central & District.
Paddington: almost too complicated to explain. What we have in effect is four separate stations
A: Mainline station - four different gatelines (one for HX only), plus some open-access platforms, used by NR,HX and early morning Elizabeth
B: Elizabeth line station: own gatelines and platforms, but has escalator link to Bakerloo (see C)
C: Bakerloo/Circle/District (towards Bayswater): three sets of gatelines, either side of Praed Street and also south of & below the main NR concourse. Escalator link from Bakerloo platforms to Elizabeth line (see B)
D: Circle/District (towards Royal Oak): separate station at the far end of the complex (approx 1/2 mile walk within the station)
As far as C & D go, it doesn’t matter which one you pick if you’re heading to Edgware Road, as both lines go there, but is extremely important if you’re heading the other way.
Bond Street-Farringdon & Whitechapel: common gatelines, separate platforms
Liverpool Street:
platform-specific gatelines for NR/Overground & early morning Elizabeth, common area for main Elizabeth/Central/Circle/Hammersmith & City/Metropolitan
This then links, via the Elizabeth line platforms and a long walk to Moorgate, connecting to Circle/Hammersmith & City/Northern & (different) NR service
Canary Wharf: three entirely separate stations, one each for Elizabeth, Jubilee, DLR.
Custom House: one station, two separate gatelines for Elizabeth & DLR
Woolwich: Elizabeth line only, Woolwich Arsenal is a 5-minute walk away
Abbey Wood: common gatelines with NR, separate platforms
Stratford: Once common concourse area for all platforms & services, mostly dedicated platforms, but some sharing between NR & Elizabeth.
Maryland-Harold Wood: common gatelines for NR & Elizabeth (& Overground at Romford)
Brentwood-Shenfield: same, but Oyster not available, Freedom passes OK