The Rail Chain Signal is a medium-sized, rectangular device with a pixel-art isometric design, featuring a metallic frame with a matte finish. It has a bright, colored light indicator (typically red, green, or yellow) on its front face, set against a dark, textured background to enhance visibility. The signal is mounted on a sturdy, angular pole that blends seamlessly with Factorio's industrial aesthetic, with subtle engraved markings indicating its function and directionality.