I'm feeling like a novice not knowing all of this

I knew Weymouth was electrified later, but still...
EDIT: You said it disappeared (although I can still see it), so...
It is a 33/1 and a 4TC.
A 4TC is a Southern Region unpowered multiple unit. Were generally pushed and pulled around by 33/1s or 73s. They also ran London - Weymouth before electrification
in with an EMU to Bournemouth the the TC came off the front and was hauled to Weymouth this the 33/1. Then shoved back to Bournemouth and attached to the EMU.
33/1s and TCs also used to work Waterloo to Salisbury.
The traction equipment was reused from the EMUs in the 442s.
Reading is correct. Bank Holiday Monday as the Southern operated Sunday service so 33/1s operated on Basgingstoke to Reading and the Western Region operated a weekday services. 50s on the mainline and 33s on the Basingstokes.
Summary: Feeling old rememdering this stuff.
Also meant to add in my view one of the best Railtours of all time was operated by a Class 33/1 and 2x4TCs. The Liverpool St Leapfrog.