Here in the PNW there is basically one corridor that would make sense as a semi-high speed (160+ kph) rail, which is Portland-Seattle-Vancouver. They are all under 200 miles from each other and connected by one road that is often very congested.

The current Amtrak route is not frequent, fast or cheap enough to be a good alternative to driving for most people.

Hourly service between them would be a boon to the whole area, and allow for a ton of flights to not happen between the cities for connecting traffic.