I very much hope that FEC (the old Florida East Coast) has the opportunity to follow through with this, even with an up front subsidy of "reasonable" size.
Despite my very strong belief in steel rail transportation, I have not seen well designed, well built out, cost effective passenger transportation systems on any scale built in the US. From light rail to high speed rail, the nature of the "beast" involving multiple political jurisdictions, long term time scales to get financing after malodorous environmental impact statements inevitably produces local hucksterism of the worst sort.
A) Routes of light rail built in the US, from San Diego on, reflect real estate development more than public need on almost all size scales. This, IMO, is a function of the length of time required from the "idea" to the build out, and, the huge number of elected public officials soliciting funds for re-election along potential ROWs. Consequently, downtown station interfaces tend to be designed PRIMARILY to serve local real estate owners. Two classic examples: Sacramento and Denver, both of which reflect the will of one man selling his schemes to smaller players under the dream of a "great downtown." * In both cases, the potential for fast and efficient public transportation through the downtown core has been ruined.
B) Commuter rail. Post war commuter rail tends to be a hybrid with public agency train operators running on privately owned track (NYC, Boston, and, Philly are different in this regard). The right-of-ways tend to be used to some extent by freight operations, and, are of at least pre-WWII vintage. Outside of NYC, Chicago, Washington, and, Boston, where commuter trains have recently been installed, the downtown station interface tends to be poor designed for train movement and well designed for enhancing adjacent real estate values.
C) High speed rail. Pure political trash with every Tom, Dick, and, Harry, having their hands into the cookie jar. Despite the single digit billions of dollars** spent on designing, politicizing, and, advertising the idea, only one moderately high speed rail (MHSR) is actually being built, and, this one on existing, privately owned ROW.
I believe that, if FEC can keep multi-jurisdictional politics to a minimum, FEC could run a very decent passenger operation, with speeds higher than anything operating in the US during the "Golden Era" for about 20% of the price that governments could do it (and I am being generous to the government part of the equation here).
I wish them the best, and, will be an active supporter of FEC's effort.
Now, if the class I railroads find that the FEC idea, assuming it is built out, can bring profits to the bottom line by improving their track infrastructure, we might see some pretty nice passenger operations in the US around 2050.
*despite the relative decline of US downtowns since WWII, the relative power of central business districts politically remains high compared to suburban jurisdictional entities. At the very least, urban core politicians have the power to quash an entire project.
**Using the figure $5,000,000,000, and discounting facility and operating expenses, at $100,000 per year per employee, we are talking about 50,000 person years of high quality employment with very little concrete having been one. I am sure the actual figure is considerably higher.