guard-rail

The inner steel rails between the main rails of a railway track. — A guard rail on a roadway, so placed as to catch the felloe of a wheel and thus prevent the vehicle from striking the truss. In wide bridges, a felloe plank is often placed midway between the trusses, to prevent vehicles passing from one side to the other. [Felloe: The circular rim of a wheel into which the outer ends of the spokes fit. Same as guardrail, or Felloe Plank. (Kremer, 2021)