Adventures and Expeditions by GASLIGHT (2003)

From the back cover of the main rulebook:
From Back Cover:

Adventures and Expeditions by G.A.S.L.I.G.H.T., Glorious Adventures in Science, Loosely Involving Generally Historical Times, opens up a whole world of adventure for your G.A.S.L.I.G.H.T. Main Characters. It expands the original G.A.S.L.I.G.H.T. game into a quick-playing, easy-to-learn roleplaying system suitable for wargamers who want to flesh out their tabletop battles, and for roleplayers looking for a lighthearted, cinematic game.

Players take on the persona of their Victorian-era characters as they travel through a world of steam-powered automata, mad scientists, lost civilizations, strange creatures, aristocratic officers and stoic sergeants.