It makes sense time wise, flights are much, much faster.
So to realistically do this, you need fast and cheap rail. No one is going to take rail, which stops at 10+ stops, and takes 7 hours for the trip.
Right now, Ottawa->Toronto isn't too bad, compared to car. Schedule says 4 1/2 to 5 hours.
Yet, you have to get to the rail station, and get from the rail station at each end.
Were I to visit my uncle in Toronto, this means a 30 minute drive to the station, and a cab to my uncle's house, another 30+ minutes.
A car removes some of this, and removes the waiting at each end. And if you drive, you don't need to rent a car, it is more convenient at the other end.
So to compete realistically, to get many people who would drive, to use the train, you need incentive. Not punishment, incentive.
So high speed rail would be good here.
This means loads of infrastructure must be build, which means you must ensure success. This means it has better not be more expensive than a car, and if you and your wife, or family are travelling, this means 10 bucks, maybe 20 per person.
Otherwise a car is far, far cheaper. Current ticket costs are silly.
Now I agree, train is better than car. But is train better than car, or plane, if it costs a gazillion to build, and maintain, and it is barely used?
And yet you're also talking about Seattle/Vancouver, in comparison to SF/LA or Vegas, where the plane is much, much faster than rail or car. So much faster.
So it has better really be fast rail here.
Yet have you looked at the fuel efficiency of fast rail? It is not as good as you think.
And the bus! Let's replace a personal car, with a hot, smelly, loud, uncomfortable bus which most people hate.
You.must be joking.
If you think the only metrix is the environment, you will 100% fail at enacting change.
I will give you another counter example here.
Dams.
For the longest time, environmentalists complained about dams. Lost habitat, they said. And yes, it is true!
Yet compared to anything, anything at all, a dam is best for the environment. Better than nuclear, solar, wind, anything!
And it is is not as if the environment is destroyed, just altered. Some animals go away, to be replaced by different wildlife.
For god sakes, beavers make lakes and dams which can be seen from space!
It is another example of short sightedness. We must enact change in a way that it takes hold, and desired.