^^^ Actually, believe it or not (I had to go back and double-check it myself last Friday after the same thought occurred to me), there's still room for the station. See where the tracks emerge from the box tunnel under the runway in the lower image? That's almost exactly where the southwestern end of my proposed platform would go. The remainder of the platform would be northeast of the box tunnel. The plans have the box tunnel maxed out at around 110' wide (preserving the full width of FEC's corridor, and they only have 2 tracks going through it, so there should be plenty of room to add 2 more tracks for passenger trains.
Worst-case, if the platform has to extend into the area where the track starts curving, so be it. Automatic platform extenders (like the ones used in old New York subway stations with curves) are still cheaper than trying to build a new box tunnel under an already-built runway embankment... though honestly, it probably wouldn't be a bad idea for them to make the westernmost box tunnel (for the service road) about 15 feet wider than it needs to be for the road alone, just in case someday they need to run passenger track #2 through it alongside the road (it's not like the train would be going 110mph at that point, anyway, so proximity of that one track to the service road wouldn't be a big deal).
> The FEC is double-tracked from WPB almost all of the way to Miami
I don't know about that... I know a big chunk of it is single-track through Broward. I think the single-track section starts somewhere around Sunrise or Oakland Park.
> From the perspective of a family of four
Remember, there's a lot of market opportunities that don't include families of four... like single twenty/thirtysomethings, or slightly older married couples without kids, who'd be *thrilled* if they could casually and easily head up to Tampa, Orlando, and maybe Jacksonville for weekend trips after work on Friday. Train @ 6, arrive by 9, at hotel by 10, showered & heading out to Ybor/downtown Orlando by 11, partying hard by midnight. As opposed to, "start driving around 6... make it to the county line by 7 if you're lucky... pull into the hotel's parking lot around 10 (if you drive like a bat out of hell and don't stop) or 11, and fall asleep because you're too wrecked to do anything else
Tampa probably stands to gain the most with regard to cross-state tourism, because right now Tampa-Miami is a *totally* awful drive to make on a Friday after work.
There's also the market for the same demographic whose parents live in Tampa/Miami/Jacksonville/South Florida. Having fast trains means being able to be on the train at 9am Saturday morning, get picked up and be at Mom & Dad's house in time for lunch, spend the day, head home after dinner, and be back in time to meet your friends in South Beach by midnight. As opposed to, "Horrid drive across the state on Friday night, arrive stressed out, spend the night on the couch because your sibling's extended family and in-laws are occupying the bedroom that's supposed to be yours and you got bumped by virtue of being single, get awakened at dawn on Saturday by crying babies and people in the kitchen, spend the day sleep-deprived & cranky, endure another sleepless night, flee after lunch on Sunday, crash & burn 17 minutes after arriving home, and nevertheless go to work on Monday morning completely wrecked and burnt after a long, stressful, sleepless weekend."
Oh, and lots of potential for travel by retirees and newly-liberated parents whose kids just went away to college. Really, the infamous "family of 4" is probably the worst possible use case for rail. Write it off as a marginal edge case that will only last ~18 years, and the remaining affluent travel-hungry demographics fall neatly into place