TF3 Detroit: Bay's Big Gun

Transformers 3 continues to film in Detroit at the Packard Plant, this time with the huge engine looking prop spotted at the location a few weeks ago. Thanks once again to J1000 we have images and video of the likely stunt doubles for Shia and Rosie work on the prop along with Michael Bay prepping for the scene. The videos show the pair as Carly jumps from the potted plant ledge to Sam's arms while the ship/guns/turbines/whatever moves. The bluescreen makes me think this is an arm or something of a bigger Transformer.

According to a post at TFW2005, the scene involves Sam "jumping from the ship to a building." A Don Murphy member and set extra sigma1 also claimed to know what the shoot was for. Of note is the invoking of Wheeljack ("Einstein") as a TF cast member but that remains unverified.

"The shoot involving the train derailed is called "Mayor's Mile" and is a continuation of the Chicago sequence. The scene itself will take place in Chicago within the movie. It involves the intro of a main antagonist, (which is the large construct with 2 turbines in the rear photographed earlier when Detroit production arrived). I won't reveal just yet who it is, but he will then transform and reveal himself to be orchestrating much of the chaos on Earth, most Autobots arrive (Bumblebee, Ratchet, Sideswipe, Wheeljack, and the Ferrari) to battle him. Prime, Ironhide, and Josh Duhamel are involved in another sub-plot that will be revealed later."