The Bureau of Steam Engineering

In The Bureau of Steam Engineering, you play as an American steam engineer at the beginning of the American Civil War who must design and duel steam powered mechs to defend the Union. Unlike other games about steam-powered robots, this game includes a “realistic” simulation of steam-powered machines, requiring you to lay pipes to connect boilers, valves, gauges, and an assortment of steam-powered weapons! (zachtronics.com)