Here comes the train.

Northern Arizona, maybe.  Rocky, mountainous landscape, no trees.  S and I are in a car traveling somewhere for fun, for a good view in the mountains.  Sky darkens.  We're heading back southwards, and the road parallels a railroad track.  I'm about to turn right onto a short bridge that goes over the tracks, when I see that a train is fast approaching and the bridge has collapsed.  Dream ends as I'm trying to stop before driving onto the collapsed bridge and being hit by the train--which anyway will crash as it hits the bridge ruins.  No idea what's happening here.