I dont see why it couldnt work (other than money required to build). Sign a deal with Car2Go and other car rental firms for vehicles at the stations. You dont really need to increase the transit systems that much. People can take trains and then rent cars while they are there or take cabs.
For Spain - I was just there and the toll roads are about $14CAD/100KM so if they tolled QE2 and increased its max speed to 130kmph then that would be an equivilent. Add a bulk cargo car to each train and you would reduce the amount of traffic DHL/FedEx/Purolator have to do between the cities and would allow them to consolidate air freight in one City (probably Edmonton).
I dont see how it couldnt work. We arent talking bullet train. We are just talking high speed ICE style train, cut the trip in half or even more. 90 minutes downtown to downtown with a suburban station in each city and I personally would take it a minimum 5 times a year.
Sell this by reducing carbon emissions and you will get the greenies on board. How many tonnes of CO2 would be reduced just by taking 100K trips a year. Future stations in Leduc and Airdrie would also be viable for a milk run style service as well. Would also reduce any future required widening of the QE2 as you wouldnt need it with an HSR
If that worked then exapanding the train to Canmore would be the next logical step but from living in Canmore part time I can tell you the torches and pitch forks would be out against it.
Benefits for Calgary would likely be increased air traffic via YYC.
Benefits for Edmonton would be the HSR would likely run along the same ROW as the future Edmonton SE line to Millwoods so that would decrease its timetable and future costs.
Negatives for Calgary - hard to find any other than maybe might lose some freight traffic located here as they would likely be consolidated at one airport.
Negatives for Edmonton - likely less air traffic at YEG but that shouldnt really matter to Edmonton because the airport is in Leduc - it would probably more convenient for people to take HSR to YYC to fly as that would likely be the location of Calgarys suburban station.
From an Alberta perspective it makes sense to turn Calgary and Edmonton into a "twin-cities" arrangement there by being able to maximize funding at one location over the other. Example Engineering funding directed towards UofC where medical funding directed at UofA.
Also, the gov would likely combine the ROW they are getting for the power line for this as that was always brought up as a possibility even as early as 1998 if they didnt want to use the CN ROW. Getting these days with the increased hype over CO2 it shouldnt be as much of a hurdle to get the Feds to amend the legislation to transporting passengers.
This brings me back to my transportation engineering course at the UofA as this was the subject matter of my paper. Hated the course and having to sit multiple Sundays in a row at an intersection in Edmonton recording the vehicle traffic was a bore, but researching the HSR paper was fun - as was my grade

The big thing that has changed since then and now is the reduced CO2 emissions. While it has no monetary value at the moment it has huge political capital associated with it.