On 21 Sep 2012, the ALP announced that Capital Metro light rail would form part of the policy platform they would take to the 2012 ACT election.
It was covered by ACT Light Rail here.
The ALP and Greens won that election, and formed Government. Light rail commencing construction formed part of the agreement to govern between the two parties.
With that mandate, the Capital Metro program has proceeded on schedule. Bids to build and operate are being considered by the ACT Government right now, with construction commencing in 2016.