Challenges & Solutions for Electronic Interlocking Adoption in Indian Railways

1. Challenges in Adoption of Electronic Interlockingin Indian Railwaysand their possible Solutions Sunil Gupta, MIRSTE, CSE, Northern Railway Dr Mukul Verma, CEng, FIRSE, FIET, MIRSTE President, HFCL

2. EI on Indian Railways • 1st installation on IR • 1987, a trial installation in Srirangam station of SR • Today 800 to 850 installations • Still about 25% of new installations are PI

3. Issues with EI • Issues with EI • Availability • Poor Redundancy management • Difficulty in Failure rectification - Training • Problems faced during Yard remodelling • Poor Redundancy management • On failure of the main system – Toggling between main and hot standby • Hot standby found in failed condition when required • Example of a recent failure in SCR

4. Poor Redundancy Management • Suggestions to tackle Poor Redundancy management in case of Hot standby • The Redundancy management algorithm/hardware needs to be ruggedised • This feature should be tested during the computerised testing under different conditions of failures • A hardware switch may be provided to force the system to unit-A or unit-B • This will provide a manual control in case of malfunction of the Redundancy management system • In case of distributed control, the ring architecture provided for the OFC should be extended to modems and communication card • To avoid complete shutdown, “Graceful degradation” should be provided to enable the local units with limited functionality

5. The Availability Issue – contd. • The second type of failure – “Standby unit when invoked, is found in failed condition” • The standby unit should be checked periodically and alarm should be raised when failure detected • Periodicity of the self check should be determined based on the availability requirement

6. Problems faced in Yard Remodelling • Data programming • Done by the vendor, based on control table provided by the Railways • Minimum control of Railways • Dependence on the vendor in case of the yard remodelling

7. A Process for Data Programming by Railways • Objective: • To keep full control of the data programming with railways • How? • Data programming in a standard format • Simulated verification at each step • Initial programming as well as modifications • To be done by railways • Reduced dependence on the vendor

8. Data Genera-tion Tool Control Table Yard data in EI Format Electronic Interlocking Yard Data Data Vali- dator SIL-2 Simulated validation Yard data Verification Format Boolean/Relay Ckt Data Programming for EI

9. Data Genera-tion Tool Data Inter- preter SIL-4 Control Table Yard data in RDSO Format Yard data in EI Format Electronic Interlocking Yard Data Data Vali- dator SIL-2 Simulated validation Yard data Verification Format Boolean/Relay Ckt Data Programming through RDSO Format

10. EI Data programming – through RDSO Data Format • One time activities • Development of a standard data format by RDSO • Contains complete info required by EI • Ease of conversion to the EI Format • Development of an EI simulator to validate the Data programmed in RDSO format • Development of a Data interpreter software by vendors to convert data from RDSO to EI format • Development of EI data validator software (required anyways) • Development of an expert group in the railways to program and validate yard data in the RDSO format

11. Step by step procedure of Data programming • Step-1: Data programming in RDSO format Data Genera-tion Tool Control Table Yard data in RDSO Format

12. Step by step procedure of Data programming • Step-2: Validation of the Data programmed in the RDSO Format through simulation Expected Output EI Simulator with Yard data In RDSO Format Event Logger & Comparator EI Output Test case Input

13. Step by step procedure of Data programming • Step-3: The Data in RDSO format is converted into EI format and programmed into the EI Data Genera-tion Tool Data Inter- preter SIL-4 Control Table Yard data in RDSO Format Yard data in EI Format Electronic Interlocking

14. Step by step procedure of Data programming • Step-4: The Data programmed into the EI is validated by a Data validator through simulation Data Genera-tion Tool Data Inter- preter SIL-4 Control Table Yard data in RDSO Format Yard data in EI Format Electronic Interlocking Yard Data Data Vali- dator SIL-2 Simulated validation Yard data Verification Format Boolean/Relay Ckt

15. Conclusion • Two issues dealt with • Loss of Availability due to poor redundancy management • Dependence on vendors for yard data programming • Improvement of Redundancy management • Ruggedisation of redundancy management system • Redundancy management to be checked under different states through computerised testing • Manual control to prevent hunting • Periodic self check of the standby unit • Graceful degradation

16. Conclusion – contd. • Reduction of dependence on the vendors for data programming • Uniform RDSO format for yard data • Converted to vendor’s format by a certified software tool • Simulated verification of • Initial Data in RDSO format • Data converted into EI format

17. Thank you Questions???