Hmmm...
Thanks for the advice, Zek!
The problem is, I've applied the fix - more than once - and I am in the situation described above. No Blue and/or Power stock visible between the couplings.
With this symptom, normally I'd go look for a missing GeoPcDx file but GeoPcDx files are present - and those for the CoachBlue variant seem to be the same as for the basic Coach version.
The \LukRailAmerica\Cascades\RailVehicles\Passenger folder's internal structure is a little unusual - I'm not quite sure why the CementHopper files are there for every variant - but it's the same for all variants and works for two of them, so presumably it works for the other three...
Another possibility is that I haven't ticked a required DLC - but what DLC would control the Blue/Power variants but not the Cascades Red/Green Coach & Baggage variants? Do the some of the Blue/Power vehicles' textures have a different source that I've not ticked?
Stumped, I am.
Guess I'll try the Fix folder again, but I'm not hopeful...
Kind regards,
John M