Coal Drag down in the valley

I heard a whistle. We were at Steamboat, skiing, but that siren song of a train whistle can't be denied. This is a shot of a train of hoppers moving through the valley below. It looked like a pair of engines at the front, a single engine at the back and another pair amidships. I'm guessing they needed that much power to move this relatively short train over the mountainous territory.