Floorless Coasters

I've never ridden one, so could someone please explain this to me: How exactly do you seat yourself on a floorless coaster? being floorless and all, if you boarded the train like any coaster you'd fall through the track.. ..I assume that there is a floor part of the train that retracts under the seat when the ride begins, but I'm not sure. how does it work?

The train needs to stop in the exact precise location every time once stopped a series of hydraulic floors come up from the sides of the track in the loading house making it possible for you to walk to your seat. once boarded this floor retracts back underneath the loading house leaving only the track beneath you. and off you go.
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