Abstract: An insulation pad for rails on sleepers, the pad comprising a base section adapted, in use, to be interposed between a rail and an underlying sleeper, and two upper sections adapted, in use, to extend over the respective upper surfaces of the rail foot, the upper sections being formed integrally with the base section, wherein the upper sections are hingedly connected to the respective side edges of the base section, which hinges are formed by sections of pad material of reduced thickness, and wherein the upper sections and the associated side edges of the base section adjacent the respective hinges incorporate interlocking knuckle and groove arrangements for resisting differential movement between the upper sections and the base section longitudinally of the hinges.