Manufacturing of railway rolling stock parts; sales of railway rolling stock parts; sales of specialized equipment, key systems and components for rail transit; manufacturing of gas compression machinery; sales of gas compression machinery; manufacturing of urban rail transit equipment; manufacturing of marine auxiliary equipment; manufacturing of electric motors; electronic and mechanical equipment maintenance (excluding special equipment); import and export of goods; import and export of technology; technical services, technology development, technical consultation, technology exchange, technology transfer, and technology promotion; leasing of non-residential real estate; property management; leasing of transportation equipment; trade brokerage.