Moving camera pods

Moving camera pods

Hi there,

I am working on a project and am required to think 'outside the box'.
The solution I have come up with involves having a pod whizzing up and
down a beam mounted on a beam fixed to the crown of a 20km long
tunnel.

What I am after is a system much like they have for dog or horse
racing, where a pod travels alonside the animals during the race.

Problem is, I can't find any manufacturers on the net. Does anyone
know more about these systems?

Thanks

Duncs