The gist of it:
- A bearing normally uses a bushing, pad or roller to move something along a rail that doesn't necessarily have to be a straight line
- The rail can be pretty much any length, depending on the actuator
- How long the bearing lasts depends on the load's weight and the speed it's carried
- Tracks come in different profiles: Flat, round rods or something more complex with polished ground surface
There's more, but it's best explained in the video itself ... enjoy!