I visited both the Republic of Ireland and Northern Ireland the other week, and it was exactly like this. I was worried at first about delays from going through

I visited both the Republic of Ireland and Northern Ireland the other week, and it was exactly like this. I was worried at first about delays from going through customs, etc. on the trip between the two. But, I took a train from Dublin to Belfast, and it felt like nothing changed apart from the currency and signage. It was great to see such an open connection between the two countries!