Two photos up, same type of railcar.
No other type of railcar ever ran on the line, toy than an occasional foray of the ugly Bullied design which ran with them, and of which there were mercifully few. This makes accurate modelling simple, as from their introduction (1953 to this line, I think) they formed virtually 100% of passenger trains into Bantry, the goods being "Bandon Tanks". On an occasional day off for maintenance, the railcar was substituted by (usually) an ex-GSWR 2.4.2T tank loco. A "Bandon Tank" might have deputised the odd time. While I've no evidence of it happening, I'm sure it probably did.
Coaching stock is important for accuracy, and presents the biggest challenge, in the form of elderly GSWR and CBSCR stock. Bredins and Park Royals made occasional visits, but really only in later years, with PRs appearing sometimes as railcar intermediates.
The oft-shown pics of the famous IRRS St Patrick's Day special has a steam-hauled train of then brand new laminates posing on the viaduct, but such carriage stock on steam train was certainly not typical - if it ever happened at all in normal service.
Thus, if accuracy is to prevail, a three car AEC set (a Bredin being suitable as an intermediate) or a steam hauled train of a bogie third, maybe a six-wheel first, and a six-wheel brake third would be right.
Most bogies in the period modelled were GSWR in origin, with at least two old, and very basic, Bandon coaches which were short wheelbase bogies. Most six - wheelers by that stage were actually ex MGWR, though I think I'm right in saying there remained at least one CBSCR one.
None of these carriages are much like anything convertible or repaintable from British prototypes, and the railcars, while pure Southhall mechanically, were also unlikely British railcars.
Thus, for passenger trains, either serious kit and scratch building, or serious compromise, is necessary.