The problem the port(and city) has is the lack of available money... so with that in mind:
How long is the S line?(how much track, b/c like what is happening in Tampa, you cant just buy a section of the track from CSX) and how much would CSX be willing to sell the line for?
Rome wasn't built overnight. Perhaps the best solution for a cash strapped community is a phased plan. With that said, there are two sections of the S-Line. One owned by CSX and 5 miles of abandoned ROW owned by COJ. Putting back in 4 miles of track on the COJ owned ROW would connect Tallyrand to FEC, which would give that terminal direct rail access to Bowden Yard.
I'll need some help determining the amount of CSX owned track between Panama Park and Georgia. It's a 10-mile stretch between Commodore's Point and the Blount Island spur off North Main Street. There is another 13-mile stretch of track between Eastport Road and Yulee, where CSX meets up with First Coast Railroad and St. Mary's Railroad. So about 23 miles total but 10 up to the Blount Island spur.
To figure out the total mileage of CSX owned track, we'll need to know how much of the 11-mile Blount Island spur (if any) does JAXPORT's railroad control? So at this point, we're looking at anywhere from 23 to 40 (i'm throwing in extra mileage for double track, spurs, etc.) miles of track.
The Orlando/Sunrail deal with CSX is $150 million for 61 miles of track, which breaks down to $2.46 million/mile. A similar number for 23 to 40 miles of track would put our number in the $56.6 - $98.4 million range.
Looking at the high end, you're getting a dedicated revenue generator, a commuter rail corridor connecting DT with the airport and Yulee, and direct JAXPORT access to CSX, FEC and NS for $40 million more than building a CSX only accessible intermodal yard. If it falls on the low end, you may be able to purchase that entire spur for the same price as building an intermodal yard.
How would this be different from just building direct rail offloading facilities?
Its in the port's best interest to have direct access to all three local rail lines and their yards. With this in mind, there's no right-of-way to build direct rail offloading facilities that connect with NS and FEC from Blount Island.
Wouldn't CSX have a much bigger economic incentive to push for this instead?
CSX may have bigger fish to fry. In the grand scheme of things JAXPORT is a small player to them. From what I understand, they have higher priorities in upgrading their facilities in other (more profitable) areas of the US.
In this scenario, would the city have to provide incentive money to a short track operator? Is that money going to come from the mobility fees, and then what type of impact would that have on the money theoretically earmarked for commuter rail and streetcar lines?
One would have to determine the revenue stood the be gained from a short line operator on those lines. In any case, I can't imagine the need to provide a short line operator incentives to serve the number of industrial clients and terminals on those 23-40 miles of track. I imagine, someone like Tallyrand Terminal or First Coast Railroad would love to be a part of such a solution.
Who would administer this? Seems likely that a new regional rail agency would be needed. Then, would surrounding counties be on board to foot the bill as well? And then how would such a new agency get proportionate money extracted from funding sources within the 2030 Mobility Plan, which is administered by a state agency(JTA)?
Good question. In Austin, their transit authority (Capitalmetro) does. However, here it seems like JTA already has their hands full trying to maintain a decent bus system.