Or maybe Congress doesn't really have as much an effect on Amtrak as we think they do?
Were it not for Congress, Amtrak would not exist. Two different Presidential administrations - Reagan and Bush - proposed to end all subsidies for Amtrak (sometimes with a vague, fictional promise that private interests would pick up the "profitable" portions).
In the horse trading necessary to pass a budget through a dysfunctional Congress every year, Amtrak is always shortchanged, with compromises that provide just enough funding to keep the trains rolling another year. But it survives every fiscal year too - thanks to the same Congress.
Such shortsighted planning has to change, of course, a point which was made previously - circa 1981 as I recall. Amazing how little the politics have changed.