They are being trialled on the Dublin-Cork services.

If people being loud on a train really annoy you, there's now an option to book a "quiet carriage".
Iarnród Éireann is re-introducing the choice for passengers on the Dublin-Cork rail service.
It was first introduced several years ago, but phased out in 2018.
Carriage G - the quieter carriage- will be marked with purple branding, and won't cost any extra to book.
Irish Rail says the option will help those with sensory issues, people who need to work while commuting, or want to enjoy their journey without excessive use of mobile devices.
If you ask me, Irish ppl in general need to learn to be quieter on trains and buses. Special quiet carriages won't cut it. Was on public-transport based holiday in July & it's quite a difference to central Europe.
— Zeno’s Last Tweet (@crankular) November 7, 2022