I believe there was nothing that specifically referred to high speed rail. It would seem that if the cities were close enough that regular rail would meet the standard, then the flights would be prohibited. Thing Greenville, SC to Charlotte. There are 7 flights each taking about 1 hour scheduled time (not including security or boarding/deboarding time). Greyhound does it in 2 1/2 hours. Amtrak w/o freight interference would be faster than Greyhound. And w/o track improvements, I wouldn't guess they could do it faster than 90MPH so we're not talking HSR here.
And the ultimate kicker here is there is an off mainline rail yard between two of the Charlotte runways. It would be the perfect place to locate an airport train station with it's own security entrance and tunnel under the runway/tarmac area.
Honestly I've been arguing for this blending of regional trains and airlines for a long time. And GSP to CLT is actually one of my biggest cases in my argument.
For those who aren't aware of this business simulation game it is Airline Empires where you manage an airline while playing against up to 300 competitors online. I've played it and developed various strategies to fill my planes using the traditional hub and spoke system with my game airline "Cascadia Airlines" and my new game airline "Trans Siberian Airlines" my bottom tier routes are all regional puddle jumpers I use a variety of the regional jets on. Right now my largest regional planes are CRJ700s that are mostly based out of OVB, SVO, CLT, PDX, TPA, and IAH. But when factor the price of the airframe, space at gates which at CLT in the game is 500,000 Dollars Per Month Per Gate. Factor in seven daily flights require 7 spaces at a gate and the game maxes you at 50 movements per gate. Factor in places like RDU, GSO, GSP, CAE, and AGS at seven flights a day on each route you're looking at at least one gate that is locked up with these short unprofitable moves. You have the expense of pilots, flight attendants, maintenance personal, and other associated support employees you are really starting to rack up a hefty price tag.
Then you look at how short some of these flights are like CAE to CLT is only 88 miles. On a jet capable of flying 500 MPH you really aren't getting any real time benefit because you won't reach that cruising speed. When you factor in taxi, boarding, check in, and security the train immediately becomes time competitive. The train also benefits because it is closer to the population than the airport. In the case of the Columbia metro a large portion of the population is in Richland county which is a bit of a drive from the airport. This would allow for a shorter drive with cheaper parking for passengers, and because it can make additional stops more cities added to the air network via train.
From playing the game I don't like wasting slots in my hub airports to the short regional hops because they end up costing more than they really are worth. Their only benefit is that the more gates I control it makes it harder for my competitors to muscle into my airports, and the connecting traffic helps fill my flights on competitive routes. I would much rather use the slots for more lucrative transcon, and intercon routes that make large profits. But imagine if we had a train service that was codeshared with the airlines allowing it to become a true interconnected transportation network.
The airlines benefit because they are able to operate with less aircraft, crews, fuel, landing slots, and gates saving money on their bottom line. While airline passengers benefit because train stations are easier to reach, cheaper parking, and more city pairs being added to the air system. While rail passengers benefit from multiple new corridors formed between regional cities that would allow connectivity between other rail corridors. While the whole region benefits from the economic activity of the interconnected rail system.
It makes too much sense not to do something along these lines.
By the way if anyone wants to play Airline Empires with me shoot me a message here and I'll send you a link to the site and tell you which world I'm in. I think it would be fun to play against some of you guys. Here are my two liveries I'm running with at the moment. Right now I'm the largest operator of B737-900ERs and B787-900s. I do have a few of the pictured B777s.