This chapter mainly introduces the icing of railway contact wires and corresponding antiicing technologies and deals with the following four aspects: (1) the hazards of the icing of railway contact wires and significances of this research; (2) the characteristics of the icing of railway contact wires and affecting factors of the icing; (3) experimental research into the icing and anti-icing of railway contact wires; (4) expert system of the icing and ice melting of railway contact wires. Through the above introduction, the paper aims to make researchers, engineers and managers who are interested in this field have a comprehensive understanding of the causes, hazards and contributing factors of the icing of railway contact wires, to let them have a basic knowledge of icing and ice melting and the current technologies of anti-icing and ice removal and finally to provide readers with an expert system that can anti-ice and melt ice. www.intechopen.com Reliability and Safety in Railway 296 1.1 Background of research into icing of railway contact wires Large, heavy ice accretions may form on objects exposed to freezing rain. These can damage or destroy structures and cause great economic and social hardship.