Is this journey realistic
 

Is it realistic to be able to make this journey? Would the connections be reasonable reliable? The journey planner suggested it but I'm corncerned that the connections may not meet in reality.

Can't see anything risky there

20 minutes at Portarlington and 16 minutes in Thurles

If the journey planner gives it, it is a valid journey, if anything goes wrong its Irish Rail's problem to get you to destination even if it involves paying for a taxi

For the Portarlington to Thurles section, your train should be ahead of the Cork train on the line, so if it's delayed, the Cork one would be delayed too.