201 project has been cancelled.
Rail is very efficient to start with, so very little change is needed.
The ICR/22k fleet is likely to get the new gearbox/stage V engine/hybrid drive combo which will deliver a reduction in fuel consumption, improved performance and emissions reduction. That would make them the cleanest and most efficient of there type in use anywhere.
Electricifcation would be great but beyond Dublin and Cork we don't have the traffic density, there is a 30 miles section of the Dublin Cork line which has only 1 train an hour in each direction. You have to get the electricity from somewhere and thats a problem.
The Germans are quickly eliminating local hauled short set operation with EMU's, but for long distance and high capacity short distance they are still going with loco + coaches, but those locos are 8000hp, 3 times our 201