It looks like overhead crane
track as used in warehouses
etc http://www.niko-ltd.co.uk/lifting-equipment/?product=1&name=Lightweight Overhead Cranes is an example
One of it's other common uses is in abattoirs, they hang the meat hooks from it and
sling the animals along on this
track, it's good for high loads.
I have built a number of Niko-based tracks in theatres and venues to move heavy equipment such as
electric chain hoists around roof spaces.
It can be very good for material handling in confined spaces. Use a small lever
hoist to lift things up onto the trolley, and
roll it around on the
track; instead of carrying it or putting it on a trolley, where that would be impractical - IE in grids where the wheels of a trolley would
drop between the slats or indeed where the fly wires are in the way.