You run an express train by skipping stops, and we don't need to figure out how... we already do it.
If the state(s) want Amtrak to cross honor commuter rail fare media, the state(s) need to chip in to cover the difference. Why should Amtrak subsidize state services? 66 sells out nightly as it is, and with the reservation system it's pretty unfair to intercity travelers that they can't buy a ticket from Penn to South Station because all of the seats are reserved from Providence and/or 128. That's also costly to Amtrak as a lower fare is taking the place of a higher fare and leaving a seat empty for most of the trip. This is why the Downeaster doesn't allow for travel between North Station and Anderson/Woburn (for example).
I don't have a problem with premium trips being extra fare, though I'd be shocked to see it. I'd also like to see on board services provided for such trips. If the name of the game is getting cars off the highway, all measures which give rail travel an advantage over the automocar need to be considered.
Moderator: Massachusetts Bay Transportation Authority, Brightline Trains
Avatar:3679A (since wrecked)/3623B (now in service as 3636B).