As I remember it, at least in the 60s and 70s, no smoking signs on train windows were triangular point uppermost and (IIRC) green in colour. No more than half of one coach would be so marked, but ISTR First Class was all smoking (at least Up North). First class had a yellow band above the doors but I seem to remember a blue sausage logo on the windows with the word First on it.
Can anyone remember what the no smoking signs looked like and if there were the blue first signs on their local trains.
Mike