Create a low-poly steam locomotive with an open-back cab. The train should have a simple, blocky design with minimal details, suitable for a stylized or game-ready look. The cab must include a basic seat, a small furnace with a door, and a simple fuel gauge on the dashboard. The locomotive should have four large wheels, a short smokestack, and a front cowcatcher. Keep the model optimized with clean topology and a limited polygon count.