Lego Digital Designer: Having Gears Interact with Toothed Bar
LDD is a design solution for static models. It is not a functional simulation tool. The gears turn with the crank handle if they are associated to the same group, but that is only because the gears, the axle and the handle share the same rotation point. The toothed bar does not share that same rotation point (and is likely not part of your "group" that contains the handle, axle and gears) and hence does not turn. If you made it part of the group, it would rotate around the center of the axle, which is not the effect you are looking for.