The impact of electrification on railway signalling systems

Railway signalling and electrification engineers face many challenges in the integration of signalling systems with traction power. Signalling involves sensitive detection and evaluation processes to determine the state of the railway and permissible train movements, which if disturbed could lead to an unsafe condition. Electrification systems necessarily involve high power and consequently the potential to generate radiated and conducted electromagnetic interference. This paper presents a discussion of the subsystems and components employed in existing signalling, and the potential impacts of electrification on those subsystems. The changing relationship arising from recent developments in signalling and traction systems is investigated. The opportunities presented by integrated control systems, bringing together the control of signalling, traction, communications and information systems are discussed.