The bottom line is that the Dallas side of North Texas now has comfortable and convenient passenger rail service to Dallas/Fort Worth Airport.The Fort Worth side has comfortable and convenient rail service to a point only a short bus ride away from the big airport.There’s a big difference for anyone who wants to catch a plane. It’s an even bigger difference for people flying in to visit the region, maybe to attend a convention or just tourists planning to stay at a nice downtown hotel and spend money. Good for Dallas. Good for DFW Airport. Fort Worth hopes to catch up in about four years.Certainly, it’s not the worst thing in the world to lag behind, and we’ve known it would happen for some time. But it should reinforce determination in Fort Worth to get good rail service to DFW as soon as possible.Dallas Area Rapid Transit launched its Orange Line light-rail line to the airport on Monday. It takes people to Irving’s Las Colinas, downtown Dallas, Southern Methodist University and Plano.It also links with the rest of DART’s extensive light-rail network and with the Trinity Railway Express, which comes to downtown Fort Worth.For a long time, it looked as if DART rail service would never amount to much — the agency was created by voters in 1983 and funded with a one-cent local sales tax. Irving residents have been agitating for completion of the Orange Line for years.But now with 85 miles of light rail serving more than 29 million passenger trips a year, the system is looking pretty good.The Fort Worth Transportation Authority, the T, is planning its TEX Rail commuter rail service from downtown Fort Worth through Grapevine to DFW’s Terminal B, just across from where the Orange Line stops at Terminal A.The biggest hangup is money. The T was formed the same year as DART but is financed with only a half-cent sales tax from a much smaller area.TEX Rail is an $810 million project. To build it, the T needs $405 million in federal new-starts transit funding.If there ever was a good time to go asking the feds for transportation money, this is not it. Congress hasn’t been able to pass a long-term transportation funding bill since 2008.Still, the T is doggedly pursuing the funding and is lining up trackage rights and taking other necessary pre-construction steps. The start date can’t come too soon.