Yeah, doesn't look like any steam turbine I've ever seen (but that is only a few). First, the blades are dull, not shiny. Second, I agree about the diameter change there. HP turbines are symmetrical, they put the steam in the center and get IP steam out both ends. That way the HP steam doesn't come near a seal. The obvious symmetrical shape identifies them for sure. Maybe that is what this is, and just the long almost axial viewing angle obscures it. The blade angles are right for that, the rear blades are pitched opposite from the front ones.
Jon