Electronic Interlocking for Big Yards

The electronic interlockings shall be capable of controlling Points and Signals in accordance with RDSO/SPN/153 and IRS/S/24 standards.

The interface requirements for outdoor gears shall be provided by the purchaser. This information is crucial for ensuring proper integration and functionality.

Field gears (devices outside the main control center) are operated through relays using Relay drivers.

The Object Controller (OC) should be located as close as possible to the field gear it controls. The purchaser specifies the location of the OC.

Distance limitations for direct feeding of an OC to the field gear are the same as those used on Indian Railways.

Protection filter modules, surge arrestors or surge protection are needed to prevent damage from surges and unwanted operation when the field gear is directly driven by the OC without interface relays.

The communication between the CIU and OCs is through an RDSO approved Mono-mode OFC (optical fiber cable) operating in a ring topology for high reliability and availability.

If the communication between the CIU and OC fails, all outputs are brought to a safe state. Network monitoring ensures the OFC network is functioning correctly.

The EI system, including both hardware and software, must meet the stringent safety requirements defined by the SIL-4 standard.

Independent validation by a third party is crucial to ensure that the EI system's software has been thoroughly checked and its configurations are appropriate.

The user railway must meticulously verify the application software that manages yard data, ensuring it aligns with the defined controls.

When applying for type approval or cross-acceptance, the EI manufacturer must provide comprehensive documentation proving the independent validation process, including the safety case.

All modifications made to the EI system after its initial validation and approval must be meticulously documented, recording the date, reason, and details of each change.

The software used in the EI system should adhere to a recognized software engineering standard focusing on safety-critical applications, like the one issued by CENELEC.

The CENELEC standard is a key reference for ensuring software quality and safety in safety-critical applications. It ensures that the software development process adheres to rigorous safety standards.

All modifications made to the EI system after its initial validation and approval must be meticulously documented, recording the date, reason, and details of each change.

A visual indicator on the VDU screen that confirms a healthy communication connection between the VDU and the Electronic Interlocking (EI) system.

A specialized cable used to connect the Video Display Unit (VDU) to the Central Interface Unit (CIU) in an electronic interlocking system.

Three colored dots (red, blue, and green) displayed on the VDU screen to indicate a healthy color monitor. The dots flash in sequence to confirm monitor functionality.

A feature that allows operators to see the entire yard layout or specific sections in an enlarged view on the VDU screen.

The VDU screen displays the current status of various equipment and track circuits using different colors and symbols.

A backup VDU takes over if the primary VDU fails due to communication issues, computer problems, monitor failure, or mouse malfunction.

The railway provides the main power supply, while the supplier of the VDU system is responsible for providing additional power for its operation.

LCD-based indication panels can be used in large yards upon request from the railway.

The manufacturer provides detailed documentation for installation, maintenance, troubleshooting, and software design. This covers everything from hardware diagrams to software algorithms and test results.

The manufacturer must secure certifications from a qualified safety assessor (independent of the manufacturer) who verifies the software's correctness and safety, the interlocking system's reliability, and the system's overall performance.

These certifications are crucial for ensuring that the interlocking system is safe, reliable, and meets the specified performance standards. This includes validation of any modifications made to the system.

The expected mean time between failures and mean time between failures to a safe state are crucial metrics for evaluating the system's reliability and safety.

The manufacturer is responsible for providing a comprehensive cable plan for the station incorporating all the necessary connections between the components of the interlocking system.

These tests ensure that the Electronic Interlocking (EI) system meets all the required safety and performance standards.

This test visually inspects the EI system to ensure components are present and correctly assembled.

This test verifies that all parts of the EI system are properly insulated to prevent electric shock and ensure safety.

These tests check the functionality of all individual components within the EI system to ensure they work as expected.

This test ensures the EI system fails in a safe and controlled manner if a critical component fails, preventing accidents.

This test ensures the entire EI system works together seamlessly and meets all operational requirements.

This test ensures the EI system is able to diagnose issues and provide valuable information for troubleshooting.

These tests simulate various environmental conditions (temperature, humidity, vibration) to ensure the EI system functions reliably in real-world scenarios.

A process that allows previously tested and approved electronic interlocking systems to be used in new projects, eliminating the need for full retesting.

The supplier of the system must ensure spare parts availability for a minimum of 25 years, holding a sufficient inventory to meet immediate needs.

The manufacturer provides training to railway personnel at their facilities on electronic interlocking technologies.

The manufacturer sets up a dedicated facility equipped with simulation tools, diagnostic systems, and test instruments to test and repair electronic interlocking components.

After the warranty expires, the manufacturer offers an annual contract for ongoing maintenance and repair, ensuring prompt repair or replacement of faulty components.

Certificates from previous type tests conducted during system development, demonstrating compliance with international standards.

A document outlining the procedures for cross acceptance and approval of software embedded electronic systems and new or imported technology products for railway signaling.

The company must provide continued support, including long-term spare part availability, training, test and repair facilities, and an annual repair contract, even after the initial approval.