The downtown transit tunnel will have two tracks, one for each direction.
This would be fine if the trains only went east and west. However, desire for travel is also north and south.
It is possible to force everyone on the future southwest LRT, and future southeast LRT, and future link to Gatineau LRT, to transfer to the east-west line. Transfers would occur indoors, be comfortable, but would still increase trip time significantly. This would be significant for those who already had to take a local bus to the BRT to the LRT transfer … etc.
Recall too that IF the southwest LRT, which should go through the airport, doesn’t offer direct to downtown service we can kiss goodbye many conventions. Apparently a deciding factor in choosing convention destinations is direct airport to downtown transit. However, if the southwest LRT went over the Prince of Wales bridge, it could easily continue on the Casino and a convention centre there. Is this really what we want? I want to be good neighbors, and the two jurisdictions really should function and be planned as one metro city, but I dont feel obliged to build a major transit system to deliver conventions to Gatineau and not Ottawa.
I like to view the tunnel as being like the existing transitway, open to many transit vehicles with various destinations. Consider if we had red trains running east /west Blair to Tunney’s, and green trains running from the southeast through the downtown and then back out to the south along the southwest route, a giant U shaped route. This not operationally difficult to schedule.
Now consider the Gatineau service. Recall that the DOTT projections for tunnel ridership assume all STO bus users are in the LRT tunnel. How did they get there? I don’t see a major bus transfer facility at Rideau. But recall that the currently planned tunnel has a spur tunnel designed into it, branching off at the east end of the Rideau St station. From there, that tunnel could someday extend under the market to a station near Sussex before crossing the river (whether in a tunnel, on the McDonald Cartier span, or my preference, taking back the Alexandra Bridge as a transit and pedestrian/cyclist bridge).
The DOTT team have specified a spur at Rideau, not a two level station with transfers. This I expect (but it hasnt been said out loud) is a Federal tourist influence. The Feds want an easy to use system for tourists and visitors and for the interprovincial LRT to have a national unity function. A one-car no-transfer service from downtown Ottawa to Gatineau is best for this. So visitors could go to any downtown station, and get on the blue train that would go to Rideau and then off to Gatineau.
It is just my speculation, but obviously the LRT could continue through downtown Gatineau and back to Ottawa on the Prince of Wales bridge, make a circle route. Or, it could be implemented in reverse, with trains from the east going through the downtown and then over the POW bridge to Gatineau, until such time as the rest of the loop is completed.
Fully developed, a multi-train multi-destination LRT service in the DOTT could consist of a east/west line, a route from the south that loops through the downtown from the east and back out to the south from the west side, and a circle route that crosses the river.
Fortunately, the interprovincial study just starting up should be well enough under way as the DOTT planning process continues, to incorporate any number of options.