A bit of rolling roof advice needed.

At 75 years I've reached the point where lugging around scopes is no longer fun.  Instead, I've decided to cut a few trees and build a simple 8' x 8' shed w/ a roll-off roof for my CPC-1100.  The roof will have a low pitch of lightweight metal sheathed construction.  I've seen photos of a number of roofs w/ large 4" caster wheels riding in aluminum channels but the cost of that seems totally unnecessary for my purposes.
In attempt to save money I'm leaning towards 2" metal roller casters rolling on 1" or 1.25" Schedule 40 PVC pipe. 
An alternative form of track I've seen was a 3-4" wide galvanized strip with a raised center shaped to accommodate the rollers but cannot find out anything about this product.  It seems it would be a little more stable and perhaps much easier to install than PVC pipe.
Anybody know what this product is called and where to find it?  Any other advice appreciated. 
Jim

Originally Posted by James DellaPenna

An alternative form of track I've seen was a 3-4" wide galvanized strip with a raised center shaped to accommodate the rollers but cannot find out anything about this product.  It seems it would be a little more stable and perhaps much easier to install than PVC pipe.
Anybody know what this product is called and where to find it?  Any other advice appreciated. 
Jim

That's a track for automatic gates.  Check on the internet for driveway gate companies.

John,
Thank you.  I've already built my observatory a year ago.  I ended up using V-groove aluminum track and rollers.  My only difficulty was finding 16' pressure treated 2x6's that were actually straight!  This proved to be a bit of a challenge.  Anyway, it's finished and my aging body no longer has to cope with the time and strenuous logistics of transporting a CPC1100 to observing sites.
Jim