City and rail officials unveiled designs for Oahu's future rail transit system Wenesday at Honolulu International Airport, because the trains will go right through the middle of the airport. There will be a rail stop between the international and overseas parking structures and lei stands. And, officials estimate 15,000 passengers will eventually board trains there daily.  They also believe as many as 20,000 airport employees could consider using rail to get to and from work. Ground will be broken on the airport rail station in 2015 and construction will finish in late 2017.