Here is a little bit of information that may be of interest for the transit commuters in Ottawa concerning the proposed downtown Ottawa Transit tunnel between Tunney's pasture to Blair Station via Downtown. Source is the City of Ottawa web site.

Identifying a solution from the core out has guided the development of a new transit vision for Ottawa. A transit tunnel through the downtown is the key feature of the new Rapid Transit Network, and is among the priority projects approved by Council by a vote of 22-2 on November 28, 2008.
The tunnel will bring a faster, more efficient, environmentally friendly and world-class - transit system to Ottawa.
The Downtown Ottawa Transit Tunnel Planning and Environmental Assessment (EA) study, to be completed by January 2010, is the first step in making the downtown tunnel a reality.
The Tunnel study will determine how we build light rail transit between Tunney’s Pasture Station and Blair Transit Station on the existing Transitway and will identify the routing of the tunnel section through the downtown core. In addition, the study will recommend where stations will be located, how transit riders will be able to access the tunnel from the street, how the stations will look from an urban design perspective and finally how the stations will be integrated with existing buildings.