In message , at 12:31:35 on Fri, 31 May
2019, Basil Jet remarked:
Incidentally, Watton-At-Stone now has practically no trains to
Stevenage on Monday to Fridays. The GBNRTT gives no hint of replacement
bus times.

There's long term engineering works near Stevenage, and I think the
replacement buses run "on demand".

There are no shortage of electric trains sitting around unused that
could run an hourly shuttle from Watton to Knebworth,

Wouldn't that involve a reversal at Stevenage?

but they can't be arsed.

Or the track's not available.

Google suggests there are three trains after midnight, which
suggests that
the track is present and correct.
Enough to run a full service, during the day?

Is bustituting an entire line on weekdays just so they can run more
trains on a different one a year before the paths to run both were
available unprecedented?

Not sure what element of that is the core of you question. Doing
engineering works ahead of time, or works on a main line needing an
adjacent branch line to be closed to facilitate it.
--
Roland Perry