Slab is a single platform to mount motor and carriage wheels.
Dig a hole (0.5 x 0.5 x 1.2m) and level Slab.
Attach the reo (1m x 0.4m).
Pour the concrete around the Slab & let it set.
Bolt the wheels and motor base directly onto the Slab (No ChemSet, no nuts & bolts).
Slide the gate/monorail onto the wheels.
Perfect gate & wheel alignment for the life of the gate.