A historical overview of railway signalling & control (or `from Bobbies to Balises´)

The paper presents a historical overview of railway signalling and its development from the opening of the first purpose-built passenger-carrying railway in 1830 with hand signals, through the developments of fixed lineside signals, electric telegraphs and interlocking mechanisms for points and signals. From the appearance of power signalling at the turn of the 20th century, it follows the development of first electrical and then electronic signalling technology through to present day communication-based systems.