The Steam Engines of Oz - The Geared Leviathan #01

In Locomotives of Oz is back in a brand new story! Lone scavenger has a chance encounter with the twins tied to the infamous past of Oz, the father looking for his lost sons fallen hero on the path to redemption, and a former prisoner of adjusting to life among rough N 'drying Munchkins. Back to the future world of Steampunk Oz is 100 years after The Wizard of Oz and answer this question: What is geared Leviathan?