I have to say that I think it is a bad idea too for Ireland.
It shouldn't take any longer than 5 years to plan for and electrify a line. The lifespan of a train is significantly longer.
The Maynooth trains are relatively new (2005?) and I imagine displacing these to other parts of the network will be tricky enough, and the order time for any new ones will be long enough.
Let's just get on with the electrification programme and have some suitable electric trains ready.