on the zipline you slide down it onto another part of the map but the cool thing is you can turn around and everything....you cant shoot on it and zombies will actually go on the zipline to follow you.......now the catapult machine flings up again onto another part of the map,however it is not automatic you still have to wait like 15 seconds before it flings you a 1000 feet in the air but its very helpful to get away from zombies

please thanks and + rep:)