Mr. O'Keefe, while "I've been away from this stuff" over 35 years, nothing has come to my attention that RPSA70 has been repealed in its entirety, although it has been amended by subsequent legislation.
The Act clearly states that the Members, i.e. the roads that signed up, or their successors, have surrendered their franchise to operate intercity passenger trains for their own account. Pragmaticly, that provision was meaningless, as all the roads wanted nothing other than "OUT". But the provision was there "just in case" some road foresaw a future opportunity to reap an entrepreneurial reward from intercity passenger trains.
Since the FEC was never a Member, because they were out during 1969, no provisions of the Act apply to them. Accordingly, they are free to sponsor an intercity train. But, should they merge with a Member road, then I would think the franchise provisions of the Act would be applicable.
Would Amtrak want to enforce? One hand says no because government agencies are not entrepreneurs - and Congress, as well as Amtrak management, wants it that way. The other hand says that Amtrak is a bureaucracy, and if there is anything out there that ruffles those feathers, is any party encroaching on that turf. Indicative of that is how many obstructions Amtrak threw in the way of Indiana and Iowa Pacific contracting with one another to operate the Hoosier State.
Best hope for AAF, if the FEC is to be sold, the State should be the buyer. But I would hope the State has enough sense to contract out the road's operations to a concern titled "Florida East Coast Railway Operating Company" comprised of the existing managers and employees. For no question whatever, they run a darned efficient outfit.