High speed rail requires very straight track with little elevation change compared to slower rail. That is the reason the swiss built the Gotthard Base Tunnel
https://en.wikipedia.org/wiki/Gotthard_Base_Tunnel. This 57km tunnel alone cost $10 Billion US. Any high speed rail to Vancouver from Calgary would most likely require a few tunnels similar to this. I think a $20-40 Billion construction estimate would be very low.