As a train passes and the horn blows, one brother covers his ears while the other stays glued to his tablet in the patio area of CorkScrew BBQ in Spring. (Photo ©Chris Wilkins/Texas BBQ Posse) If you like eating barbecue and watching trains there may not be a better spot in Texas to do both at the same time than CorkScrew BBQ in Spring. Located a short distance from Union Pacific’s Lloyd Yard, where freight trains are assembled, the tracks split within view of CorkScrew’s outdoor eating area. One set of tracks heads north and another turns west, running just…