When the frame carriage move 2 sand blocks , the block from the top fall through the frame.
That's a cool mod and improvement of the rp2 frames, congrats bro
EDIT: oh, and also, if i power an engine with a lever on a frame that the engine moves, the structure Infinitely moves; and if i break the lever while moving, it makes all the structure disappear
(sorry if my english is bad )