I emailed the person that originally uploaded it on Live Leak (who is none too happy with the video on youtube) and asked him about it. Here's what he told me:
It was filmed in Romania while on vacation. The route is used only about once a week to access a nearby mine. The train usually consists of the locomotive one boxcar and a carriage, though they rarely have any passengers to justify the carriage. Most of the route follows along the shoulder of the road, and as you can see it gets very grown over. Due to its proximity to the road, the signs in this particular stretch (being something around five KM) are removable. Typically the Engineer would stop the train, walk forward and remove the sign, then move the train past it before replacing the sign.
At this location, the track curves away before heading off in the direction of the terminus; as you can see from when the video starts. The engineer confessed, after stopping the train, that he thought he could just clear the sign and not have to worry about removing it. Understandably he had been a bit irritated about the repeated stops and starts, and just didn't want to bother in this case.
