How to swim with Nessy. As far as Deeprun Tram exploration methods goes, this one is by far the easiest
Note; you will need to be a gnome to do this, though I would assume that it would work with goblins and dwarves as well. I can't say for sure, however. It would be appreciated if someone can do this with a dwarf or goblin so we can know
Also, pygmy oil will not work if you're trying to turn your character into a gnome.