In summary, is it that trains stop running by 19:00 or start declining
from then?

I ask because I am confused by the accounts so far.

Eg TFL say on their website

"The RMT leadership plan a strike from 18:59 on Tuesday 9 June to 18:58
on Thursday 11 June, with normal services resuming on the morning of
Friday 12 June.
Customers using the Underground on the Tuesday evening are advised to
finish their journeys by 19:00 to ensure they get home, as services are
likely to decline after this time."

Now I know I'm an old pedant but if they are on strike from 18:59 it'll
be a little odd to find any of them still driving trains after 19:00.

Is it more in the nature of a rolling stoppage with staff walking out as
and when they reach the end of the line? If so, when do station staff
walk out and force station closures?

--
R (a.k.a. confused of Hackney)