[Balero]

That route at the top would make any high speed rail pointless. You would never get up to a speed to make it worth while. All to stop at places like Castle Rock population 2500. Going down to Eugene and Salem would make sense, but with the intent that they places would aim to grow in size considerably.

Places like Gresham to Forest grove are better for the Portland tram network, they are just part of the one metro area, they are not different metro areas like Seattle and Portland.

[SllX]

You can cut some of those out then if you think they don’t make sense. It was a quick and dirty example I came up with from my minimal knowledge of Oregon/Washington geography (not nothing but not exceptional) and tracing a route through Apple Maps. Anyone with better knowledge of the local geography can take a second pass and come up with something more reasonable.

You do want some local service at some in-fill stations though between the major destinations, even run express and local service, but as long as you can park your car at a station, having a station that the more suburban/rural parts slightly off the beaten trackway can go to still makes it accessible to more people in the State.

[Balero]

Yeah absolutely! A local service that works well alongside a high speed intercity one would be greta, though may be better to build after the main route (don't want some small stations slowing down the main route build).

For the East/West corridor slower speed trains at the same stations allowing transfers would be preferable (cheaper and quicker to build, with minimal speed impact) to high speed rail.

[SllX]

Ah, express and local service are terms of art used by at least Caltrain that I may or may not be wrongly assuming is more widespread (although another commenter below mentioned it’s used by the Shinkansen services in Japan as well which I think I knew but forgot). They have their “baby bullet” service which amounts to: these set of trains in particular skip a bunch of stations along the way, and the local service just serves all of them.

You can run them on the same tracks with the same stock. You have e.g. the 9:00 express train depart from Portland serving a subset of the stations between it and Seattle and maybe the 9:15 departs and serves all of them followed by another express at 9:45. Each stop shouldn’t add more than 2 or 3 minutes between terminuses, if the service stops for a generous amount of time at each one.

And then yeah, you have your regional transportation agencies to serving the metro areas along the way more comprehensively.

[sbierwagen]

Big HSR systems have a mix of express and local trains, like in Shinkansen: https://en.wikipedia.org/wiki/Shinkansen#Service_names Not every train stops at every stop.