I don't want to get into too much speculation over a hole, however.
You couldn't see how deep the hole was, but the hole the digger was sitting in was digger deep. The hole it had dug from there was probably twenty or thirty feet deep. So a total hole of maybe 30 or 40 feet I reckon.
I'd suggest, this is for the hydraulics that operate "the secret bit" - which is almost certainly a controlled drop with effects to make it seem like a much higher fall.
If this hole gets bigger though (like coaster train length), then we may actually see the train drop into it. At the moment though I'd say it's doubtful.
If you have farcebook (and maybe if you don't), you may or may not be able to see Rach's photos here (sorry to steal them Rach, but people are clearly desperate
![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
).