I suppose that anything is possible, but I'm not sure that it would be a good thing.
First, you'd loose the ability to book one trip across the country easily, unless provisions are made to keep Amtrak at least at the ticketing level. Next, it could lead to more transfers, again unless some entity retains control of the equipment and leases it out to the RR's or something like that. Next you need to change crews everytime you cross to an new RR. And then there is the issue of trains that don't stay on one companies tracks.
Finally, what do you do if one freight Co opts out? Run no service in that area? Keep Amtrak for that area?
This is not exactly on the same wave lenght but it does bring up a question I've often wondered about. How were coast to coast reservation made when one had to use multiple RR compaines for the trip? Did one company make all the arrangements?
I lived in Chattanooga. My sister lived in San Francisco. I would go down to the station or city ticket office in some cities (no Julie, no 800 numbers) and gave my order to a living human being. I would make my reservations to leave on L&N's Georgian.At Evansville it would become a C&EI train to Chicago. In Chicago I would change trains and stations to the California Zephyr and would ride it to the coast. It was a Burlington train Chicago to Denver, then D&RG to SLC and then Western Pacifc to SF.
The only reservation he could make for me on the spot was from Chattanooga to Chicago. He would have to wire ahead to Chicago for Chicago to SF;wire to SF for SF to Chicago and finally wire to Chicago for Chicago to Chattanooga.It could take a week or two to hear back from all of them. I doubt that satisfying "fat little Billy Haithcoat" was a prioriy in the hallowed halls of CUS.
My railfare ticket stubs would show this:
Chattanooga to Evansville L&N
Evansville to Chicago C&EI
Paramlee (bus cab, van,etc) transfer service between stations in Chicago(Dearborn to Union)
Chicago to Denver Burlington
Denver to Salt Lake City D&RG
SLC to Oakland (instead of Emervyille as it is today) Western Pacific
bus from Oakland to SF proper(as is done today)
then for the return the same stubs in reverse order.
FInally, there would be four slips of paper showing the pullman space:
Chattanooga to Chicago
Chicago to Sf(or Oakland,strictly speaking)
SF(Oakland) to Chicago
Chicago to Chattanooga
Wait, there is more. If you were in coach, normally they would get each ticket as your interline(if it was and many were) train changed railroads. In the above example, that means at about 3 a.m. in Evansville they would go through the coaches waking people up to get the C&EI ticket.
Sleeping car passengers did not have to face that.When you were put in your room they took all tickets that they woud need until you physically changed trains.
As for a coach passenger on the CZ, it was unique in that they collected all tickets when you boarded that they would need to the rest of that specific trains journey. On that particular train they did not disturb coach passengers every time the train moved from the tracks of one operator to those of another. But on most they did disturb you.
Many of you know of the Santa Fe RR. It had huge trackage and most if not all of its trains were self-contained within its track, thus it advertised "Santa Fe all the way". I guess the only interline work it had with other railroads was in transcontinental sleepers to NYC and such places. Of course in that case everything would be collected from the passenger as they boarded--I guess--I never rode in one.