We trialled a walking floor for bulk domestic waste to landfill site. The operation was as described earlier with floor planks that rise, move back a few inches, then return whilst neighbouring planks rise and move back. This caries the load to the rear of the trailer and drops it out the back door.
Advantages -
No tipping gear to raise the body with a risk of falling over in high winds on unstable surfaces.
Disadvantages -
Slower discharge than tipping or moving bulkhead
Spreads load over a bigger area
Does not push the vehicle forward away from spoil
Requires more complex hydraulics
On balance we preferred the moving bulkhead to push the load out.