The invention relates to a self-propelled carriage suitable for traveling in a gallery of substantially cylindrical shape. The carriage comprises a chassis (1) made up of two wheel sets (14); a skip (10); and a horizontal longitudinal support axis (16) on which said skip is pivotally mounted. Each wheel set comprises two arms (24, 26) each having a first end pivotally mounted on one end of said axis; two rotary drive shafts (32) extend orthogonally to the support axis and are mounted at the opposite ends of the arms; drive means (38) for rotating said shafts; and two wheels (40, 42), each wheel comprising a hub (54) secured to a respective drive shaft, at least one circular disk secured to the hub, and having its periphery fitted with a plurality of rollers mounted to rotate freely about axes that are orthogonal to the axis of the wheel.
