Amtrak is a transportation company, not a tourist train. They got you from Chicago to Seattle, which is what they supposed to do. Remember, taxpayers help fund Amtrak. I certainly do not want my taxes funding a tourist train.
I suspect the sightseer lounge car was "bad ordered" at the last minute - the car was not road worthy and they did not have another one available.
As others said, you could ask for some compensation, but they will not, and should not be expected to, refund your fare. They will probably offer you a small voucher for future use.