Pertains to composite hollow core station post insulators consisting of a load-bearing insulating tube (core) made of resin impregnated fibres an insulating filler material (e.g. solid, liquid, foam, gaseous - pressurized or unpressurized), a housing (outside the insulating tube) made of polymeric material (for example silicone or ethylene-propylene) and metal fixing devices at the ends of the insulating tube.