Ireland's first ever light rail system, well not exactly. We had trams and took them out to relieve the conjection, not we are putting them back in to solve congestion. Aparently trams systems are ideal in small towns with large wide boulevards, which Dublin isn't. Anyhow:

LUAS cost around 800 Million Euro

http://www.oireachtas-debates.gov.ie/D/0470/D.0470.199610300027.html]Some more government chats on the subject here

Archiseek discussion