I knew someone would ask me that at some point (actually I was getting worried no one did, lol)

do you know what an esculator is? (the moving stairs)

a travelator is a little bit like that, but rather than moving stairs, it's a moving platform that moves you from one end to the other (you get them at airports, I've seen a couple at the supermarket near me, you get them sometimes in big complexes like malls)

sometimes it moves you by itself, and sometimes you need to walk along it

I think that's (or hope that's) a pretty good description of a travelator