Amtrak is a government funded rail transportation service, isn’t it? why is it the only rail service for passengers, was there some kind of bill or law stating that it can be the only one or is it just the fact that passenger rates aren’t as steady as freight, and sometimes can be money-losing?
Passenger service was a money-loser for the railroads. In order to fix that problem, the government formed Amtrak. Amtrak owns the intercity passenger franchise on all the participating railroads so that no competing service can be started up except through Amtrak.
When the Rail Passenger Service Act was first passed in 1971, Eugene Kerik was in the opening phases of establishing Auto-Train Corp. The law was written in such a way that “railroad auto ferry” services were grandfathered to allow operation alongside Amtrak. This permitted Auto-Train to operate as a separate private operation for several years before it ran out of money. I’m not sure how American European Express got to run its luxury service before it also ran out of money.
I’ll bet the regularly scheduled AOE trains technically ran as Amtrak trains and were arranged with the host RR thru Amtrak. Most excursion trains, such the E8s specials over NS, operate this way now.