Avoid compliance
A good approach would be for Amtrak to just ignore the requirement, or avoid compliance by technically complying with the law in a manner that means the law is ineffective. Congress has little enforcement power, since it wants to fund Amtrak, rather than eliminate it. The amendment in question was from a powerful Member of Congress (in terms of writing the Amtrak bill) likely as revenge for both houses funding Amtrak at a much higher level than he would have preferred.