http://w5.montreal.com/mtlweblog/2009/08/bus-vs-tram-clarification.html

http://ville.montreal.qc.ca/portal/page?_pageid=4577,7761623&_dad=portal&_schema=PORTAL

There’s not much detail in English on the city’s website, I’m afraid – just these glossy highlights: http://ville.montreal.qc.ca/portal/page?_pageid=5957,40443575&_dad=portal&_schema=PORTAL&t=1

While the downtown/Old Montreal loop certainly seems to have its drawbacks (not the least, a new bus route along here that hasn’t been particularly successful – http://w5.montreal.com/mtlweblog/2009/08/bus-vs-tram-clarification.html), it doesn’t actually fall afoul of humantransit.org’s criteria that you’ve referenced – according to the analysis document on the city’s website, it’ll be “à double sens” (two-way). (See the PDF doc for Phase 1 linked to on this page – http://ville.montreal.qc.ca/portal/page?_pageid=4577,7761623&_dad=portal&_schema=PORTAL)

The downtown/Old Montreal loop also links a number of large institutions, has strong touristic potential as it provides direct access to the length of the Old Port and Old Montreal, ties together the new and old downtowns (which are ever better integrated with the covering over of the Ville-Marie Expressway and the development of the Quartier International – though I think there’s still a perceptual distance-gap between the two in many Montrealers’ minds – as well as a steep hill).

There are also a couple of huge developments pending at the southwest* corner of the loop – Griffintown and the former postal sorting station site – which would also be served by the LRT to the South Shore** that had been proposed as part of the conversion of the Bonaventure expressway into an ‘urban boulevard’ (there’s no mention of that – not sure what the status is, but it would be a regionally driven project rather than a city one). And there’s the new CHUM superhospital at the eastern end.

The Phase II line along Notre Dame is shown on the other city documents as joining the network along Rene-Levesque, which makes far more sense for commuters. Not sure why they’ve shown it intersecting at rue de la Commune on the google map version on the city’s web site. That whole stretch of Notre Dame is slated for redevelopment as an ‘urban boulevard’, quite contentiously as parts of it are proposed to be a freeway trench separating the neighbourhoods from the waterfront. I’m not sure about the future of the freight lines there – the parts nearest the old port are already being developed for housing.

There’s also been recent talk from the suburbs about trying to get further extensions on the Metro – closing the gap on the orange line so that it becomes a closed loop, and adding a few stations on the the yellow line beyon Longueuil on the South Shore.

*Note: Montreal’s street grid is at a 45-degree or so offset from north-south. But many Montrealers aren’t even aware of this as the convention is that streets roughly parallel to the river are “east-west” (eg rue Notre-Dame, av du Mont-Royal), while the perpendicular streets such as Pie-IX and du Parc are “north-south”. So the three spines you mention as being “north-south” would be incomprehensible to most Montrealers – the alignments along Rene-Levesque and Ste-Catherine are east-west. The third spine isn’t downtown – it’s on the port side of Old Montreal, which is primarily a touristic and leisure area (though with increasing numbers of residents).

**(Bizarrely, the ‘South Shore’ suburbs are pretty much due east of downtown)

I’m not terribly familiar with the street layout east of the core, in the Mercier–Hochelaga-Maisonneuve borough, but I would think that running the tramway along Ontario or Hochelaga instead of Notre Dame (if the street widths permit) would make more sense, even if the route puts it closer to the Métro. One of the current candidates of mayor supported that routing early in the planning (don’t know what her current opinion is).

I feel obliged to point out that your map is oriented in the local way, with the (false) assumption that the River flows from west-to-east, and that Laval is due north.