Thank You, Fred Frailey.....

That's what we are trying to work out. If the railroads want more money form amtrak , why don't they demand it ?. Is there some legislation , or possibly arbitration ruling , that prevents them from doing so ?
I think its probably more a case of the railroads can't be bothered, its usually one train a day, why spend hours negotiating over it ?

Regarding the legal requirement mentioned somewhere above obligating Amtrak to cover only incremental costs, I'm wondering whether a successful argument could be made that incremental costs must include the opportunity costs of sacrificing the number of freight-train slots necessary to give preference to an Amtrak train.

Passenger trains have run late since time immaterial, for any number of unpreventable reasons.
The problem we have now, besides Amtrak causing its own delays via mechanical and crew shortage shenanigans, is that some railroads have drastically reduced their physical plant in order to stay alive.
Good examples of double track routes out of Chicago since reduced to single track CTC include the MILW, IC(G), and GM&O.
At least the tradition of good passenger service on the MILW manages to persist thanks to the duality of Chicago and Milwaukee - the double track stays alive up here all the way up to milepost 104, as opposed to on the Carbondale and St Louis lines where it once quit before MP 40.
It was claimed back in the bad times that a single track CTC railroad could handle roughly 75% of the traffic a double-track ABS railroad could. It was an easy selling point by the signalling companies and installation contractors - RR traffic was down, and there was big money to be made for them if they could successfully sell the proposal.
Even in spite of contractual and managerial differences, most RR's do generally run Amtrak as best as they can. The problem is that the physical plant doesn't exist to get Amtrak around even their normal volumes of freight - not to mention periods of exceptional volume.
I'm not laying blame on the old RR's for cutting down trackage - they needed to do it to survive - but heck if that still doesn't remain the biggest dent in passenger train timekeeping today.
(I'll mostly exempt some of the big western long-haul routes, as they never were anything more than single track, and a pax delay 80 years ago on their road still would mean the same pax delay today.)
I feel that there was a failure of the public sector, during the 80s and 90s, to recognize a problem, and to step in and directly help keep up that double track mainline over which so much public commerce traversed.

Double full CTC track over single track CTC has many advantages. For traffic that has different speeds of trains the need for long sections to get around slower trains is important for RR fluidity. Of course the faster the fast train is in relation to a slow train the quicker the fast train can get on the preferred direction of travel track. The more ton miles of traffic line the more there will be the required maintenance windows to keep the track up to its designated track class. Then you have an enforced single track section. Single track RRs have to have hours long maintenance shutdowns piling up trains. An extreme example is the BNSF southern transcon. It has 50 MPH general freight, 70 intermodal , and 90 + SW chief. If the SWC can quickly pass the 50 freight then everyone keeps going but any single track section the SWC is on then everything goes into the toilet especially if the SWC has to wait for a 50 train to clear the single track section. The more a RR wants Precision Scheduled RR the more 2 Main tracks it needs.