Light bonds are provided on the rail joints of what type of rails?

The correct answer pertains to the use of light bonds on bolt running rails. In railway systems, bolt running rails are typically laid in configurations that can require electrical continuity and stabilization at rail joints. Light bonds are used in these instances to ensure that electrical connections remain strong while accommodating the mechanical movements of the rail.

Light bonds are not typically utilized with heavy rails, standard running rails, or deformed rails because these types usually rely on different methods of joint connection and electrical bonding to maintain their integrity and safety. Heavy rails would often employ more robust bonding systems due to their specific operational requirements, while standard and deformed rails may require different configurations of electrical and mechanical connections to perform effectively in their respective applications. Thus, light bonds are an appropriate choice specifically for bolt running rails, making it the right answer.