Incidentally, Irish Rail don't sell platform tickets; however, it always pays to politely ask ticket-checking staff if you can gain access to platforms - they're usually very accommodating.
If you want to see some action at Connolly, it is a closed barrier system, so you need a rail ticket. It costs €1.50 for a single to the nearest city-centre station (Tara Street - less that 10 minute's walk from Connolly). The same price will also get you to Pearse, the next station southbound after Tara Street.
This information is aimed at the modern enthusiast, rather than at preserved railways (although you will find links to both categories).
Live camera view with a reasonable view of Butt bridge. If you're very sad (like myself), you can stay on this site continuously [it should auto update] during your coffee break until you see the Rosslaire coming up mid-morning.
Luas-the movie (well, almost! Driver's eye views of Red and Green lines - Feb 2007)
Luas tips (practical info)
Latest Luas pictures here (February 2007)
While the Republic of Ireland is quite a small country, it still manages to run a reasonable railway service. Dublin is the hub of most rail lines which radiate from the capital; the exceptions being the (Ennis)/Limerick - Rosslare line and the Ballybrophy-Limerick services. There are also branch services from Manulla Junction - Ballina and a suburban service based in Cork. Train fares to other parts of the country tend to vary but compare quite well with the UK (and not so well with Europe). Rail Rover tickets are recommended if you are touring and/or staying for some time.