I was on the Silver Vista (8:45 train) this past Tuesday and there were indeed two sections to the third (9:30) train.
As it happened, we drew 486 for the day (481 had a bum air compressor), but 486 ended up having compressor and throttle difficulties -- 473 (on first section of the 9:30 train) took both trainsets and 486 up from Tacoma. Was a really neat operation, nicely and professionally handled. 482 (Train 3 Extra) did end up picking up the McPhee off Train 3, I believe as the crew suspected it was too heavy for the 473 and what power the 486 could provide.