I posted about this in the WRGMG thread, and the possibility of a chunnel type deal with car transportation especially in winter.
What sticks out for me is that I don't understand what company would ever want to finance, build and operate a railway. CPR and CN had their transcanadian network built for them by the government, and I don't think either of them have invested in any new lines since they've become private (correct me if I'm wrong)?
What really seems worth completing this project now (depending on ridership growth) is the low interest rates, and the time-value of money in favour of getting this project done now rather than in the future.
Maybe the best option for Alberta is to go at this almost in a
Deutsch Bahn (German Railroad) way. Have a company, majority controlled by the provincial government, that owns the railway, and what-not, and maybe you sell off shares to private industry. I am not convinced that private industry can effectively operate an extensive, and sufficient public railway system, and the general consensus among tax payers is that they can't trust the government. SO why not remove it from both, but give the government the upper hand.
I think there's market potential if such a "at arms length of government" company were to be established. If they twinned a track between CGY and FtMac, in theory they could also accommodate relatively high speed freight. HSF is something that I'm pretty sure does not exist in NA.