I'm going to chime in, since I DO have construction experience - being a commercial construction manager.
There's a difference between a mistake, and a decision that may not be the best solution but solves another problem.
They have completely enclosed the large lift's mountain, meaning the track will have to be maneuvered into the ride building and hoisted into place - including the enormous lift components seen in the photos linked to previously.
My guess is that Disney wants to get as much of the heavy machinery in and out of the jobsite before November as possible. And perhaps even start dressing the mountain to make it look nicer once guests are surrounding the jobsite. To do so, they had to sacrifice the logical step of installing the track first. The track probably wasn't ready, and they had to proceed.
Now they're going to have to get those pieces inside and up - quite a feat. danlb_2000 is quite right when pointing out that their sequencing is not the most logical - but nobody can say it was a mistake. Someone would have stopped them from capping the lift mountain at some point, since the missing track isn't just something you "forget". You forget to run a conduit or rough-in for a water connection - you don't forget to install the track before you enclose the building.
Not a mistake, just not the ideal or most logical sequence of operations. There's some reason they chose to do it this way, and it's likely what I said above - get the cranes and concrete trucks off the site so that they can minimize heavy traffic through the park come November.
The "mountain" section you are referring to is not completely enclosed in, just on one side of it. The heavy track seen in the photos on Screamscape is for the lift part of the ride, and just might be installed on the "open" side of this "hill"
. The more regular track can be more, or less, easily maneuvered into position, IMHO. I've seen hollow tubular roller coasters (Matterhorn had a hollow system pressurized with Nitrogen I believe for structural integrity monitoring.)
I believe you are moving in the right direction when it comes to choreographing a job like this, and 100% they don't want to have to bring in and out the heavy machinery in the middle of the night . . . by November, major structural work would be done I am guessing, track should be put in place and major mountain structural work done.
Unless, of course, they build a construction wall corridor to the access road between Mermaid and Storybook Circusland.
Of course 7DMT is on a schedule, but Disney always does a very safe job when building things (at least they used to), and I don't think they'd do anything to jeopardize the attraction, such as moving a very heavy piece of the track into an enclosed part of the ride . . . seems like a great way to damage something.
So, I do not agree that a compromise was made in terms of what is being discussed as the heavy lift components sure won't be maneuvered into the very small amount of enclosure that is built, like I said, a lot more is going to be built.
I apologize to danlb_2000, I wasn't trying to maliciously "put words" in his mouth, but given that he described the construction choices as "not making sense" and went on to describe how they would have difficulty putting track inside . . . if I heard somebody say this on a construction site about a project, I would figure it was a "mistake" instead of a carefully weighed chess move under time constraints, which seems a little farfetched, IMHO, despite the scenario you suggest.
I wasn't sure if what danlb_2000 said was a "hoax" or something like that, like maybe he was trying to be provocative, it was almost kind of comedic, as if somebody was watching Splash Mountain being built and thought that the hole was too small for the logs or something . . . it just didn't make sense to me!
I think we've all been had by a clever poster! He's probably laughing and seeing how many times he can make us explain what is going on!
I thought that this side of the mountain was a "down" part of the ride, hence heavy lift mechanism not needed.
