A unitary clamp adapted to fit in a part circular opening defined by two arcuate arms having a gap between their opposing ends that are formed on a vertical upstanding wall of a clamp plate having a base for resting on a sleeper in which the base of the clamp plate is to carry a rail that is parallel to the clamp plate upstanding wall and the clamp is to fit in the part circular opening and engage both the clamp plate and the rail. The clamp has a unitary member of two generally C shaped sections each having upper and lower curved arms joined by a central member, and a cross-connecting piece at the end of the central member at one of said upper and lower arms of each of the two sections to place the sections spaced apart and generally parallel to each other. The cross-connecting piece has a curved shape conforming to that of the part circular opening to engage the interior of the two arcuate arms of the clamp plate upstanding wall part circular opening, with one of the arms of the two clamp sections resting on the clamp plate base and the other arm of the clamp sections to rest on the rail.