yep, officially.
That video is an updated one (last year) of a film shot by the same guy a few years ago, notice in the opening shots he has to traverse supports sticking out of the rock, local officials had the concrete removed from this since I was last there to prevent all but the most foolhardy of giving it a go. People still do though !
It was built between 1901 and 1905 to allow power station workers access for maintenance and to cross from one side of the gorge to the other.
Plans are for them to renovate it and charge an admission fee

Whether I get to go on it or not (doubtful my missus will be with me) the area is absolutely stunning

Simon