In the episode 30 Days Without Accidents Michonne returns and Rick opens the gate. But what kind of pulley mechanisms can make that work? Especially when you don't have electric motors like the garage door.
I can understand the gate from the castle where you use gravity. To raise and lower the gate. But here you have two doors, one to the left and one going to the right with the same rope? And then how do you reverse the process to close it?
I imagine if you have something like a bicycle gear you can place a vertical pole and rotate on both direction, but then you need two chains (one for each door) and a very long chain to connect to the main gate. And how do you make it strong enough so walkers don't break the pole, hold that big door, and also smooth enough to rotate it remotely.