Amtrak gets some 40 cents per passenger mile in federal subsidy.  Roads and commercial aviation get around 1-2 cents per passenger mile.

The State of Oregon subsidizes Amtrak to the tune of $16 million/biennium; while Greyhound, Bolt Bus, and the numerous other ground transportation providers are forced to compete with ODOT/Amtrak, don't receive any subsidy; and have to pay a wide assortment of taxes.

If motorists had to "pay their share" in Oregon - nothing would change.  If Amtrak patrons had to "pay their share", nobody would dare ride the train.  Too many people complain Amtrak is already too expensive, even though they don't come close to paying the cost of operating the train (nevermind the cost of borrowing money, capital investment, depreciation, etc.)