DEER LODGE, Mont. For nearly a century, passenger trains rumbled three times weekly through this broad, grass-rich mountain valley in central Montana, home to more cattle than people, until Amtrak pulled the plug on the North Coast Hiawatha in 1979. But with a new president known as “Amtrak Joe” and Democratic control of both houses of Congress, a dozen counties across the sparsely populated state are hoping that a return to passenger train.