KSL TV PROMONTORY SUMMIT — Workers at Golden Spike National Historical Park are busy preparing their two steam engines for the summer season. It's still about a couple of months before they ring these bells for real. But for engineers like Tom Brown, the excitement is already well underway. "Oh yeah," Brown said. "Yeah, this is the best job in the world." Like a kid at a train museum, Brown spends his hours doing what he loves. The Union Pacific's No. 119 and Central Pacific's Jupiter locomotives were actually built in 1979. "They're both replicas, but they're down to within about a quarter of an inch of the originals," Brown said.