Looks like I`ve found it. What a way to squeeze it in!
If I`m reading right, the `spur` would actually be a part of the track that allows the upper part of an individual car to slide sideways off the actual ride system - the bogie is attached to the elevated rails by 2 wheels on top, two on the outside, and one underneath in each of it`s 4 corners, much like a rollercoaster assembly. However, ontop of this chassis is a second platform with the pivot on it; I`d guess this can be removed sideways onto some sort of trolley and taken sideways into the elevator.
It looks like this area is around the 84ft level? I`d guess in the darkness right after Rome burning? Either that, or around the 115ft level; opposite the boy and girl on the videophones before the globe - opposite the original Network Ops Maps - but I suspect this may have been in conflict with the right hand side 1982 Network Ops / Comms Center mentioned earlier? Or down at 52ft, just after the Future City laser diorama, before the last descent- but that places it on a curve, something I doubt would be done when removing ride vehicle bodies.
The ride storage and maintainence room itself you mention looks to be next to Wardrobe and Ride Control, down in the underslung utility level at the 28ft level?
Sorry for the thread drift; rest assured I`ll be back up in 180top very soon! To prove it, here`s a googled image of a modern Genie boom lift (though on wheels)
http://www.teamlorenz.com/images/garage 174.JPG - this makes sense since it`s located ontop of the final ascent tunnel roof area; this area is offset from the center of the Geosphere, where the hatch is, and would have to swing out and up to reach it.