Assuming that is indeed a sub section, it could indicate that sections are premade in another hall, perhaps the large hall north of the object. And then moved into the large hall to the east. Since the completed sub also needs to exit through same end of the hall, the sections either need to be moved by gantry cranes inside the hall, or they are moved around on the rail set parallel to the rail set that houses the finished sub. If so, then each section would somehow be moved laterally, via some sort of movable rail blocks.
The gantry crane idea seems much simpler and efficient though.