A warehouse fire near the Portland station is restricting train traffic north of the station until further notice. Several trains have substitute bus service between Portland and Seattle, and some trains are still operating, but only as far as Vancouver, WA.
Currently trains 506 and 517 are serving all stations between Seattle and Vancouver, Washington. Beginning Saturday August 8, trains 505 and 518 also will resume service between Seattle and Vancouver, WA. At this time, those traveling in and out of Portland and wishing to travel on these trains will need to arrange to get to and from Vancouver themselves.
Another option is to change your ticket to a different time where buses are being substituted for the entire ride between Portland and Seattle, stopping at all stations. Trains with replacement buses are southbound 502, 504, 508 and northbound 503, 507, and 509 (and 505 and 518 on Friday August 7). Trains 500 or 511 have been cancelled completely, with no substitute buses available. Trains between Seattle and Vancouver, BC, and trains between Portland and Eugene are running normally.
For help with ticketing options contact Amtrak at 800-USA-RAIL.