In reading the posts elsewhere in the forums about HSR, it occurs to me that the DFW Airport Board should be thinking more proactively about accommodating rail in future projects... and not necessarily High Speed Rail.
The current model of rail for the big airport is bringing tracks in from the north, certainly no direct line from the centers of population in the area. The trains are going to terminate at different terminals, A for Dallas and B for Fort Worth. There is no service from the south where a significant part of the regional population lives and works and where much of the other transportation infrastructure is located. Recent rumors hint that a talked-about connector HSR line from Dallas to Fort Worth might somehow manage a stop at the airport.
The point was made in another thread about how certain airports incorporate a centrally located rail station that can zip a traveller off to a city center or other, further destination; just a set of stairs or an elevator away. I think of Schiphol Airport, just south of Amsterdam, but also close to other cities such as Rotterdam, Den Haag, Utrecht, and several other cities and towns in the region, sort of a "Dutch Metroplex". Schiphol is the main international airport in the region, although there are other smaller commercial facilities such as at Rotterdam. Underneath the central terminal at Schiphol is a well designed train station that offers at least three types of service; a set of local-connector lines to surrounding cities, express trains to major centers, and high-speed Thalys providing links to Antwerp, Brussels, and Paris. High-speed to Germany is available at the Amsterdam Centraal Station to Germany and Switzerland via Utrecht. I note that a major airport can be a station on a HS rail line or feed into one at another station in the city, either way works. Another point is that HS rail does not exist in a vacuum; many other rail lines exist to complement and supplement the Thalys and Intercity Express HSR lines in the Netherlands.
Back to DFW Airport. It is becoming apparent that the current renovation of Terminal A, built over 40 years ago and smack-full of asbestos, is taking too long and costing too much. Once this is finished work can move ahead on Terminal F. But in the meanwhile Terminal C, the last of the original passenger facilities not having been revamped, is being left alone; no improvements of any kind, not even basic service upgrades and cosmetics. One conclusion is that AA wants a NEW Terminal C, which lies at the center of their domestic route system. It would seem to be easy and somewhat "cost effective" to "flip" the blueprints for Terminal D and just take out the international facilities. In any event, it seems that a new rather than rebuilt Terminal C would be one of the options considered when the time comes to do something about it.
What I would propose DFW Airport Board consider if they spring for a new Terminal C, is to include provision for an underground full-service passenger rail station. Given the amount of excavation necessary for constructing the most recent Terminal (D) it should not add greatly to the cost of a new ground-up Terminal C, which sits in a central position among the other terminals, along with Terminal D. Even with the billion-dollar SKY-LINK system getting around from terminal to terminal is somewhat of a hassle, especially when the power fails or there is lightning in the sky. There are a couple of sky-bridges between D and C and between A and B but they are not centrally-located and few people use them. Building C as a central distribution point, from incoming trains at level 1, to local flights at level 2, and connecting flights in other terminals on level 3 with moving sidewalks or mini-trams or monorails going back and forth might help to make getting in and out and around the airport a more efficient experience, especially given the shorter connection times that are a part of AA's new schedule. There would be some kinks to work out as one would expect. For example, an underground station would not accommodate the planned diesel trains from Fort Worth very well unless extremely well ventilated. Perhaps these plans would not be ready until when the TEXRail operators would be ready to switch to electric. A station could be built with room for expansion, so that at some point in time other lines, maybe even HSR, could provide more convenient transportation options for residents and visitors to the area.