Free travel (inculding trains) for resident pensioners is universal in Ireland, although seems to now be under attack from the usual sources.

There is a similar arrangement in England (not sure about Wales) and in Scotland too with the enhancement of free travel for resident under 22s and also on Citylink coaches (Glasgow- Aberdeen, Inverness- Edinburgh etc)- inter-city express coach travel for pensioners is not available in England as far as I know.

Seniors in UK can get a discounted railcard for a fee, free travel on trains is only available in Ireland, although there are local schemes for discount train travel in Scotland & maybe elsewhere?