The trading company ITG Railtours Ltd. was wound up about two or three years ago. Since then they have organised one tour (run under the auspices of the ITG itself), to Sligo with the RPSI Heritage set back in March 2010. They've also run a few mini-gala type events at the DCDR.
I suppose there isn't really the same opportunity to run loco hauled tours in Ireland as there was in their heyday.