On Google Maps, look up "Alleghany Valley Joint Sewage Authority". The crossing mentioned in the news report looks like the access road to the aforementioned facility. No gates or flashers, just a crossbuck with a stop sign.
At best there were 2-3 car lengths between the crossing and the bridge. It appears the locomotive made it across before overturning (you can see it's wheels and traction motors peeking out of the underbrush behind the reporter), gondolas and tankers went into the drink.
---PCJ