We have something very very similar in the White Mtns of NH. Instead of a rail, it's a concrete slough (Think the like the trough that a cement truck uses to pour cement). However, there is nothing to hold you onto the track on ours, unlike the one in the video that looks like there are rollers to keep you from coming off of the track. I took a look at the related link the you tube poster showed. The coaster he was riding does have breaks, he simply opted not to use them.
In the related video you can see a conga line of people all stacked up. That happens frequently at the one up here as well, which is why I rarely go anymore. A person gets on and then rides the brakes all the way down. This causes many people behind them to queue up as they catch to the slowest person in the front. It's very frustrating to behind someone who is scared and riding the breaks.
Conversly, many years ago the admiral got a bit confused on the stick and for some reason forgot the pulling back is brake and pushing forward is go faster. She panicked in a tight turn and pushed the brake, making the sled go faster, until she was goin too fast into a turn and flipped off the course. Lots of road rash from the cement track. She's was a good sport about it and we had a good laugh. Nothing a little bourbon won't fix to dull the pain.