Any private entity can impose performance metrics on any other private entity by contract. The difference is that for Amtrak the freight railroads are required by law to accept what Amtrak stipulates for some lines - it's not an agreement negotiated between willing parties (at least for the core system/long-distance trains) for all terms. Of course, if you've ever read a 'shrink wrap' software license you probably know all about contracts between unequal parties.

The more important underlying note, I think, is that this ruling combined with the one about takings in the last Supreme Court session suggest that somebody with the right case could go after the "common carrier" concept itself (and most regulation, for that matter). Arguably, if you privately own the trains and the tracks, why should you have ANY responsibility to the public other than paying your taxes and not causing a nuisance beyond what's necessary by your just being there and covering your liability for whatever goes wrong? I smell a case like that cooking ... somewhere. John Kneiling is smiling (he advocated abandoning railroads as common carriers and restarting as private lines), wherever he is.

Further appeal is a certainty. But the current Supreme Court might not be interested in the case, or might use it to go farther. Could be dangerous ... and could be the end for Amtrak if they have to actually negotiate as a shipper with the railroads. Note: state-supported trains are not necessarily in this situation - deal is between the RR and the state in most cases and Amtrak is just the operator. And the RRs get a good deal of improvement out of public funds as part of the deal. Then there's the NEC, where Amtrak owns the railroad and the private freighters (if any) are the tenant - roles reversed there. And finally: makes HSR look like an even better idea - separate line for passengers.