“I said, ‘See those railroad tracks?’” Mr. Heller, a Nevada Republican who lost his seat later that year, recalled in an interview. Nuclear waste to be carted to Yucca Mountain for permanent storage would have to travel along the tracks, within a half-mile of the hotel, Mr. Heller said. “I think he calculated pretty quickly what that meant,” Mr. Heller said. “I think it all made sense. There was a moment of reflection, of, ‘Oh, OK.’” Whether the waste would have traveled along those particular tracks is a subject of debate. But the conversation appears to have helped focus Mr. Trump, who in recent weeks seemed to end his administration’s support for moving nuclear waste […]