I don't get this as a point against a valid successful oo model. Tara wagons only run Navan to Alexandra Road with trips to Limerick works as required. Shale wagons, (which I'm looking forward to aswell BTW) are even more limited in run area.
In regards to gauge, thats just something we deal with, has to be overlooked for the greater good and all that....
But yeah, the CAF Mk4s can stay on the very long finger imo, so much more interesting Irish models to cover.