In near 100-degree heat last week, Benito Velasquez and three co-workers pounded into place the S-shaped clips that hold steel rails to concrete ties. A ping reverberated down the track with every sledgehammer blow. Three or four swings, and the clip was in place. Repeat on every one of 8,450 ties. By mid-November, said Mike Schrake, general superintendent for contractor H&H Engineering and Construction Inc., trains that now cross Fairchild Air Force Base will instead head toward Cheney.