1 Death of Insanely Overpowered Fireballs: SO MR NEWTON, WHAT IS THE GOAL OF THIS MAD SCIENCE THAT YOU WANT ME TO ASSIST WITH?
2 Isaac Newton: We wish to construct giant mechanical beings! Powered by steam!
3 Death of Insanely Overpowered Fireballs: STEAMPUNK MECHA. GOT IT. BUT WHY?
3 Isaac Newton: To advance science, obviously!
4 Death of Insanely Overpowered Fireballs: OKAY, SURE, I GUESS...
4 Isaac Newton: Taller shoulders to stand on!!

Mecha are pretty cool. But the obvious way to make them even cooler would be to make them steam powered!

Mechs in games like BattleTech are powered by fusion reactors and operated by computers and electrical circuits. Converting the idea to a steampunk setting is a fairly obvious extension, and there seem to be a handful of games and fiction works in which the idea is used, but I couldn't find anything especially well known.^[1]

But yeah. A big steam engine, and you control the mech using enormous levers that open valves to let high pressure steam run through pipes, combined with mechanical control rods and gears and stuff. It sounds awesome!

I mean... it would be a great contribution to science.

[1] Before another million people write to me, I missed Girl Genius. And Wild Wild West apparently. Honestly neither of those showed up in the first page of Google hits for "steampunk mecha", so it's not entirely my fault.