Saw the video was from 2007.. looked for an update. It was designed in the 1970s. This was the first system, and was installed in 1989. It's a 2mi loop. In 2013, they installed a 0.6mi line at a Brazilian airport.
That's a lot cheaper than light rail.. but it's hard to do a fair comparison, because of the labor difference and light rail projects (at least in the US) include stuff like tunnels, re-routing highways, etc.
https://en.wikipedia.org/wiki/Atmospheric_railway#Aeromovel
They're working on a new 3.75mi line in downtown Canoas BR. http://www.aeromovel.com.br/en/projeto/canoas/
In this 1993 article, they say this cost $9m US to construct (using local labor and materials) and $500k/yr to operate. http://articles.latimes.com/1993-01-17/business/fi-2255_1_tr...
That's a lot cheaper than light rail.. but it's hard to do a fair comparison, because of the labor difference and light rail projects (at least in the US) include stuff like tunnels, re-routing highways, etc.