I had a situation in Ruby Cave, which was pretty familiar to me from CR. One digged a tunnel right into the ground and wants to push something over the entrance. A lorry would fall down and yep. Well done..., you can forget it as long as you don't build an elevator. But building an elevator isn't cheap (material cost, check for energy supply). To prevent such situation you could build a loam bridge, which isn't a good solution if you take both paths, the one into the ground and the one on the surface, often. Then the elevator would be the best, but expensive solution. As long as there is no floor door.... :



The elevator would be still useable for lifting up things such as lorrys.

Anyone interested in this might want to have a look at \planet\Experimental.ocd\Hatch.ocd