In article , Richard J.
writes
snip
why don't they put some
big signs on the tunnel walls opposite where the cab window stops? (X
on the wrong side, tick on the correct side, or something like that.)

Why not, indeed? The mainline railways (well, Southeastern at least -
don't know about the others) have "open doors other side" notices
attached to the CCTV monitors on the "wrong" side at many stations -
but not *all* stations, and I don't know how they decide whether they
are necessary.
--
Bill Borland