"Paul Scott" wrote

'The Highwayman' - left Newcastle very late pm, took the coastal route
through Sunderland, arrived FP about 0600. Travelled on it once in the
late
60s - don't think it ran for long though, it was a bit like a fully seated
sleeper...

IIRC the Highwayman was a day train - though the routeing was as you state.
It ran, again IIRC, in the early 1970s, and although it was something of a
dead-end in development of rail travel it proved the need for lower fares
for leisure travellers. Before then long distance tickets were basically
limited to Ordinary Singles and Returns, though there had for many years
been Mid-Week Holiday Returns (Summer only, out and back on Tuesdays,
Wednesdays and Thursdays, return within one omonth of outward journey, but
not in teh same week). After the Highwayman, Economy and 17-day Returns were
developed, which were the forerunners of Savers and Supersavers.
As for overnight cheap trains you may have been thinking of Nightriders
which ran, IIRC, in the 1980s between Scotland and London. At one stage the
Nightrider seated portion of the overnight Aberdeen to London train
wasmarketed by and liveried for Stagecoach, this time as the forerunner of
rail privatisation.

Peter