This paper focuses on key technologies of heavy haul railway catenary system advanced intelligent monitoring system (6C+ system), particularly under the increased transportation demands and prolonged use of catenary equipment. Researched and established a digital technology based catenary system intelligent monitoring architecture. The purpose is to establish a comprehensive monitoring system for catenary system covering sensor network, edge computing and cloud edge integration. The research is based on the 6C monitoring system of Shuohuang Railway catenary system, to solve the scenarios of high traction current and heavy pollution, as well as special sections such as viaducts and tunnel entrances and exits. Utilizing technology of IoT and wireless sensor networks, the research emphasizes state monitoring of vital structures in the heavy haul railway catenary system. This paper offer a detailed analysis of the improved 6C+ system's application in the Shuohuang Railway Catenary, assessing the effectiveness of technologies in network design, sensor adaptation, and equipment surveillance. The research results can be used to guide the intelligent and digital upgrading of heavy hual railway catenary intelligent monitoring system.