This strike has been brewing for months if not years at this stage. It is beyond comprehension why Irish Rail haven't figured out the contingencies for various categories of customers at this stage. Their twitter widget on this page (
http://www.irishrail.ie/industrialaction) indicates that they are replying to queries on twitter saying that an announcement re annual passes will be made early in the week. Again, why can't they say this as a matter of general publication.
The normal mechanism in the event of a 2 hour delay is to issue vouchers to the value of 1/480th of a pass, so I would guess we'll get vouchers to the value of 1/240th for each missed weekday if we ask. In theory you should also be able to ask for the Sundays as well, but they might be a bit stickier about that. While the tax people might have a problem with it, I would think it would be a waste of effort to put in a mechanism for collecting the resulting revenue.
What is of concern is that it all appears to have gone very quiet in the media. So either there are proper talks going on and nobody wants to bugger them up by making statements, or the unions just want to haul everyone out to make a point. My money is on the latter.