Noting their plan is to go all the way to Tampa, is it safe to assume it will be in direct competition with Amtrak over CSX utilizing yet to be granted trackage rights?
I'm pretty sure they're planning to build in the ROW that was originally set aside for HSR. They've already said any new tracks west of Cocoa will be grade-separated and up to HSR standards, so there's really no sane reason why FDOT would refuse to let them use it. For all intents and purposes, FEC picked up a copy of FDOT's "incremental high(er)-speed passenger rail vision plan" from around 2003, dusted it off, and announced it was going to build it almost exactly as described. Remember, every study that FDOT has done has projected that intermediate-speed passenger rail between south and central Florida (let alone Jacksonville) would make a real profit. The thing that's always killed it was the cost of buying ROW from CSX or FEC -- a problem that FEC obviously doesn't have.
I don't even think CSX is going to fight about it very much. CSX obviously stands to lose some intermodal business to competition from FEC, but I see FEC's market as being Florida
itself. CSX is slow and lumbering, but they own tracks covering half the US. FEC could conceivably run tracks down I-75 to Fort Myers or Naples (for passenger & intermodal freight), and maybe even Tallahassee, but at the end of the day, its tracks basically end at Jacksonville, and the only market where FEC might be someday where CSX has no presence at all is Southwest Florida (a market it once had, then abandoned). CSX collects bulk goods IN Florida, and carries them OUT of Florida. FEC will be the railroad that takes goods delivered INTO Florida and distributes them around our increasingly-urban state. In this sense, FEC is more like a European railroad than a traditional American railroad. They exist only in Florida, but they have the potential to completely own the market for passenger and intermodal rail traffic in this state someday... in effect, finishing the job Henry Flagler started more than a century ago.