It's an option if money is no object, and you have lots of time. Train travel in Canada is not like on Europe, sadly. There's like three trains a week going from Edmonton to Toronto, from where you can get what looks like one train a day to Halifax. That costs the same as the full flight, and if I flew to Scotland and took the train from there, I'd be traveling for a week to get to where I'm going. I realize it's still a marvel to be able to do this at all, but it's just not going to be practical in the near future.

(Edit: changed "never" to "in the near future". Never is a long time :)

That being said, I overall agree with the sentiment of traveling as little as possible and by the last impactful mode possible.