Breznice to Pisek depends on which service you're catching. A stopping train (
Osobni Vlak) usually terminating at Protivin will be a
RegioNova. The fast
(Rychlik) services (heading onwards to Ceske Budejovice) will be run by Arriva. They're usually
845 DMUs, which are ex-DB 628 units.
Pisek to Tabor looks to be mostly booked for
842 DMUs. (Click the bold numbers/names for pics).
I mean, by UK standards, they're all reasonably interesting. The RegioNova units have a rather lively ride as they're just rebuilt
810 units (which are still knocking about on lightly-used lines).
If you visit
ZelPage (
https://www.zelpage.cz/razeni/) you'll get *most* booked compositions for Czech trains so long as you know the number of the train you're catching (Muj Vlak app will have this). So, you can have a play about and see which lines have the preferred traction.
ZelPage also has last year's compositions which
@59CosG95 might find useful for digging out timetable info.