const Msp::GL::Object *get_bogie_object(unsigned) const;
const Msp::GL::Object *get_bogie_axle_object(unsigned, unsigned) const;
const Msp::GL::Object *get_rod_object(unsigned) const;
const Msp::GL::Object *get_bogie_object(unsigned) const;
const Msp::GL::Object *get_bogie_axle_object(unsigned, unsigned) const;
const Msp::GL::Object *get_rod_object(unsigned) const;