I need this to explain how to build tunnels on slopes of medium height.
Do you mean having double height slopes from the scenario start-up?
In this case you could do some terraforming in the .sve file by just loading it as a normal game and then save it.
I think it's important to explain well the tunnel construction when the slope is of average height, because it can be a little difficult for novice players, it is for that reason that I use slopes of medium height. ;)