In the ever-evolving new generation of railway technology, Solid State Interlocking (SSI) and Computer Based Interlockings (CBI) stand as pivotal innovations shaping the future of rail signalling. These advanced systems have a significant impact on the safety, efficiency, and reliability of railway operations worldwide. As the industry continues to embrace digital transformation, understanding the nuances between SSI systems and CBI systems has become crucial for railway professionals and enthusiasts alike.
This article delves into the world of modern railway interlocking technologies, exploring the historical development, technical aspects, and practical applications of both SSI and CBI systems. By examining their strengths, limitations, and real-world performance, readers will gain valuable insights into the current state of railway signalling and its future trajectory. The comparison between these two ground-breaking interlocking systems technologies, sheds light on the ongoing evolution of rail safety and operational efficiency in the digital age.
Historical Development
The evolution of railway interlocking systems and components has been marked by significant technological advancements. In the early stages, manual signalling and routing systems relied heavily on the expertise of signalmen . This approach, while effective, was labour-intensive and prone to human error.
Mechanical Interlocking
The 19th century saw the invention of the lever frame, which allowed for centralised control of points and signals from a single signal box . This innovation used metal rodding and wire runs to connect levers to point switch blades and signal arms, respectively. Many of these mechanical boxes, known for their robustness and reliability, are still in service today .
Relay Interlocking
The advent of electricity led to the development of relay interlocking. This system used large quantities of BR930 relays to perform the same logic as a lever frame . Route Relay Interlocking (RRI) implemented control rules through Boolean logic using electromechanical relays . While effective, RRI installations required thousands of relays, resulting in high costs and lengthy timescales for installation and maintenance .