Bottom of silent cartographer
After you get to the ledge get a wart hog in there first...
You have to look at the left and youll see a ledge with a light drive your warthog of to that ledge...
Then drive it off that and you'll be at the bottom it is pretty hard took me few times...
If you need more help, we've got more Roller Coaster Tycoon cheats and also check out all of the answers for this game
Comments for this hint