Action by the Fort Worth Transportation Authority board last week was a major step toward getting proposed rail service from downtown to Dallas/Fort Worth Airport back on track.Plans for TEX Rail, a $810-million project to extend commuter train service to the airport and Grapevine, had been stalled for some time, partly because of a delay in receiving federal funds that would pay 50 percent of the cost and partly because agreements had not been worked out with railroads that owned tracks needed for the operation.In the meantime the Dallas Area Rapid Transit system (DART) moved aggressively to link its central business district to DFW, announcing earlier this month that it would begin light rail service there Aug. 18, a full four years ahead of Fort Worth’s earliest projections.The board of Fort Worth’s authority (also known as the T) indicated last week that it had reached an agreement in principle that would allow TEX Rail to use DART tracks that run from the Stockyards through Northeast Tarrant County, which would allow the service from Fort Worth to get to the airport. The T’s president was authorized to sign contracts with DART and with Fort Worth and Western Railroad, which also owns trackage rights needed for the downtown-to-airport connection. The authorization will expedite moving the process forward during August, when the board will not meet. It is not a done deal yet. But it looks good considering how long it has taken to get to this point.Even when those accords are completed, there’s another part of the track puzzle that must be solved before TEX Rail can start running trains to the airport.Still unsettled is the use of tracks owned by Union Pacific Railroad between downtown Fort Worth and the Stockyards. We can only hope that negotiations are continuing there, and both sides can come to terms relatively quickly.As it stands, commuter rail service from Fort Worth to DFW is not likely to happen until 2018 at the earliest. To ensure that date isn’t pushed back further, the T has to stay on track.