Which makes complete sense, as the lead locomotive gets cut away, then loco #2 takes the Seattle section and either moves to a different track or leaves town, I don't know which. Then loco #1 backs down to its lounge + 2 coaches + sleeper, hooks up and leaves town for a long, scenic ride along the Columbia river to Portland.https://discuss.amtraktrains.com/login/
I got to watch it in daylight last time, on a very late #27. Bratkinson's description is pretty accurate. Here's the photo I took of re-attaching the loco to the SSL, before taking off for Portland.