After much delay there is now an interim solution for booking a bike space on a train.
You must book online and the bike space must be reserved at the same time as you purchase your ticket. If you buy two tickets you get two bike spaces, so if traveling in a group where only one needs a bike space they need to book separately
Flat bike fare is 6 euro single or 12 return this is cheaper than current fares for most medium to long distance journeys
On most trains the name of the bike owner should be displayed electronically at the bike rack
More information and feedback on Dublin Cycling Group’s Facebook page
Articles in Independent.ie and IrishTimes.com
Irish Rail’s announcement page, and their page on cycles and trains