Freight railway plays a more and more important role in China freight logistics industry. The traffic volume is increasing at an annual growth rate of more than 6%, which enhances the importance of increasing carrying capacity of marshalling yards. By using intelligent technologies like satellite positioning, image recognition, and Iot (Internet of Things), methods of accurate marshalling-yards operation data obtaining, transmission and processing are illustrated in the paper. Cargo wagon loading situation inspection is taken as a case study, and explains how to establish an accurate real-time data base for lean operations management, provides an optimized operation process, and displays a control query interface, which increases both safety and efficiency of the operation process.