The Rodrigues rail was about long, smaller than the red rail, but with proportionally longer wings. It may have weighed at least . Subfossil remains exhibit a large variation in size, which may reflect sexual dimorphism. It had bright grey plumage, perhaps flecked with white. Its beak and legs were red, and it had a red, naked area (or wattle) around its eyes. The cranium of the Rodrigues rail was slightly elongated, convex in every direction, and compressed from top to bottom in side-view. The cranium was medim-sized among Mascarene rails, long and wide. It had a narrow, long frontal region, at its least width.