Elevator's Platform won't move, How can I fix this?

local elevator = game.Workspace.Elevator
local platform = elevator.Platform
local start = elevator.Start
local finish = elevator.Finish
local bodyPosition = platform.BodyPosition

while true do
    bodyPosition.position = start.Position
    wait(3)
    bodyPosition.position = finish.Position
    wait(3)
end

How can i fix this script? I've tried adding more force to the body position but it does not help. Suggestions?

Edit: The Platform just stays in place, it doesn't, move i'm confused as to why.