I've entertained the thought of building a radial piston steam engine for a few years. I just happened to acquire 5 pneumatic actuators that are pretty much what I envisioned making the thing with. So the idea is rekindled and I've been devoting more than average thought to it. A few questions have come up - why are steam piston engines no longer used? All the nuke stuff that I'm aware of, that runs on steam, uses turbines. Are turbines more efficient than pistons? Seems to me like pistons would be more efficient since they capture the expanding gas and use it over a period of time instead of just letting it blow straight through; pneumatic power tools seem awfully wasteful to me.