Powered roller Conveyors

Popular for moving rigid-based items (boxes, crates, bottles etc). Unlike gravity rollers, these systems allow packages to move UP inclines, as well as being stopped/started, or to control merging/diverging lines.

Chain-driven tight-bend roller conveyor
This "roller" conveyor uses disks on a common shaft to accomplish a very tight bend.
Chain drive
With the side-guards removed, you can see the drive chains linking the "rollers" together
Curved chain-driven roller conveyor
A slightly more conventional chain-driven roller bend

Lineshaft Conveyor
A lineshaft conveyor, whereby individual rollers all connect to a common drive shaft via rubber bands. This remarkable system deserves a page all to itself.