At a booth off the beaten path

Hank has the kind of brain that always needs stimulation. He usually satisfies this by learning something new or conducting experiments, but he already has several experiments with his mutation reconstruction formula running and physical training is taking up all his other time. Which is why he is now sitting in a booth away from the main paths of the bar (reducing the chance of being interrupted) and working on a mental exercise.

Can the Tetsujin actually be constructed?

He's already deep into drafting blue prints of possible structures and is certain it would require a nuclear power plant, if not a couple. Pistons, or piston-like engines seem the best route for the limbs and fingers. How to ensure it would stand upright, however? A gyroscope perhaps? Could the gyroscope also function as a protective cage for the power plant?

Or maybe a system of cables for the fingers and limbs, somewhat like a muscle structure?