Construction labor subcontracting, construction engineering construction. General items: Manufacture of mining machinery; sales of mining machinery; manufacture of environmental protection specialized equipment; sales of environmental protection specialized equipment; manufacture of lightweight building materials; sales of lightweight building materials; manufacture of specialized machinery for building material production; sales of building materials; manufacture of new building materials (excluding hazardous chemicals); manufacture of railway locomotive and rolling stock parts; sales of railway locomotive and rolling stock parts; manufacture of high-speed rail equipment and accessories; sales of high-speed rail equipment and accessories; sales of mechanical parts and components; sales of mechanical and electrical equipment; leasing of machinery and equipment; technical services, development, consulting, exchange, transfer, and promotion; industrial design services; undertaking engineering construction business of the parent company; engineering management services; engineering technical services (excluding planning management, survey, design, and supervision).