Endless War Train

Two massive armies are locked in an endless war aboard The Iron Meridian, a colossal armored train stretching farther than anyone has ever been able to explore. Nobody knows who built it. Nobody knows where it is going. And most importantly— it never stops. The train races endlessly across an enormous world of mountains, deserts, ruined cities, frozen wastelands, underground tunnels, and open plains. It cannot be stopped, and neither army has ever successfully reached the front or rear of the entire train. The war has been going on for generations. Soldiers are born on the train. Cities have been constructed inside its carriages. Entire military bases occupy individual cars. Some carriages have become so heavily fortified that they're essentially miniature countries. And the war never pauses.