Manufacturing of railway locomotive and rolling stock parts; manufacturing of specialized equipment (excluding licensed specialized equipment manufacturing); manufacturing of teaching models and teaching aids; manufacturing of environmental protection specialized equipment; manufacturing of metal structures; sales of mechanical equipment; sales of railway transportation infrastructure equipment; sales of teaching models and teaching aids; sales of railway locomotive and rolling stock parts; sales of environmental protection specialized equipment; sales of mechanical parts and components; sales of electronic products; retail of computer software, hardware, and peripherals; sales of rail transit specialized equipment, key systems, and components; sales of metal structures; sales of pneumatic and electric tools; installation services for general mechanical equipment; maintenance of electronic and mechanical equipment (excluding special equipment); repair of specialized equipment; research and development of mechanical equipment; leasing of mechanical equipment; technical services, technical development, technical consulting, technical exchange, technical transfer, and technical promotion; industrial design services; air pollution control; manufacturing of general equipment (excluding special equipment manufacturing). Licensed projects: construction engineering construction.