I think your right, the left icon is definitely already in BTB as the edit track surface tool. So the right must be for a new tool, asking us which we prefer might imply that both will be available in the future. Not just an improved track surface editor, but a new, alternative one?Hmmm... the left one is already into BTB interface.
It means edit track cross-section points.
I'd prefer the second one which ideally would allow edit points of track independent of cross-section, using a brush tool as terrain editor does. It's being indicated by new Piddy's signature.
Too optmistic? : )