dowlingm: I thought as much: there were crossover renewals not that long ago. What seems to be in preparation now is a complete renewal of the layout: new crossovers and turnouts to the loop: also all the sidings appear to have been lifted and new ones laid down. (Incidentally, the line limit is 80 on the up line, while the down line is subject to 25 mph as part of the preparation works.)
Mark G: you hope that these works will mean 90 or 100 through Lisduff: well I wouldn't bet on it: Ballybrophy was completely dug up and relaid at great expense and its still 70 mph. Limerick Junction has been re-signalled and all pointwork replaced, including high-speed crossovers, but it's still an incredible 25mph Up and Down for about a mile!. Even for stopping trains this imposes delays.
There appears to be gross incompetence in the Limerick area: the Junction is not the only place where a lot of money has been spent and the max speed is still a crawl.