This same little tree ruined my photo going up. I wish the Park would send a logger to take care of it. You can tell this is a downward bound shot from the direction of the smoke and the fact that a brakeman (blue shirt) is poised for action. On the way up, they sit. On this mountain the locomotive pushes cars up the mountain and then backs down so there is no problem with smoke in the cars on the way up except for a short period between the switchbacks. Going down, gray/black smoke is often joined by white excess high pressure steam released with considerable noise. At this incline, the engine going down is mostly there to brake and stop a car from running away.