1. N KASHINATH CSTE/P/S.RLY

2. TPWS PROJECT Provided on Chennai Central/Chennai Beach - Gummudipundi section of Chennai division Section length- 50 RKMs Date of commencement- 24.02.05 Date of commissioning- 02.05.08 Total EMU rakes covered- 41 rakes

3. TPWS BENEFITS Ensures safe movement of trains under its supervision Prevents over-running of the movement authority (MA) Automatically brings the speed of train within permitted limits in case of over speeding Prevents train from entering danger zone if the driver fails to control while approaching a ‘RED’ signal.

4. e JB e Switchable Balise e Fixed Balise JB LEU Cabinet Existing Signal Location Box A CO TRACK-SIDE EQUIPMENT LAYOUT DIAGRAM Infill Balise Existing Signal Note JB-Balise Junction Box LEU-Lineside Electronic Unit Not to scale Data Cable

5. OBC BTM Brake Valves On Board- Cubicle Wheel Sensor JB Wheel Sensor JB Antenna ON BOARD EQUIPMENT LAYOUT DIAGRAM OBC-On Board Computer BTM-Balise Transmission Module JB-Junction Box DMI

6. RE-TRAINING OF MOTORMEN After commissioning a second round of training organised for improving their confidence New motormen were also covered Operating instructions of TPWS to motormen revised and made more comprehensive

7. PERFORMANCE MONITORING Ansaldo staff stationed at both ends of the section To ensure switching ON of TPWS Monitoring condition of TPWS at commencement and end of journey Motormen recording en-route failures in the EMU log book for onward transmission to TPC.

8. FAILURE ANALYSIS On-board computer logs periodically downloaded Logs analyzed using specially developed sorting software Problem noticed on Track-side and On- board system solved to the extent possible Track-side system became fully stable

9. ON-BOARD PROBLEMS PENDING RESOLUTION On-board system sometimes not booting System Failure (SF) sometimes while booting SDMI on the run sometimes going blank Brake application due to speed bouncing on SDMI Brake application in the non-driving rear motor coach

10. MITIGATING UNRESOLVED PROBLEMS Experts called from Ansaldo France, Australia, Italy and Hong Kong They carried out detailed observations in field Error logs of OBC studied Error logs sent to their countries for analysis by specialists

11. CAUSES IDENTIFIED BTM-Antenna communication failure Error in Train Interface Unit (TIU) Error in Odometric (speed sensing) system Back EMF from Electro Pneumatic (EP) brake relay and solenoid valve coils Bugs in SDMI software and hardware in- adequacies Rear coach on-board system getting shut down during run in Sleep Mode

12. BTM-ANTENNA COMMUNICATION FAILURE Due to antenna impedance mismatch Standing Wave Ratio (SWR) found more than the tolerance limit of 1.2 to 1.4 Interference from EMI

13. CORRECTIVE ACTION Antenna protection cover modified BTM to Antenna Tx/Rx cables shielded with copper braids firmly connected to body PROFIBUS and CTODL cables between OBC & BTM shielded with copper braids BTM configuration files modified

14. TRAIN INTERFACE UNIT ERROR Communication problem between CBOP and MTORE cards in OBC Noise/Ripples in the 110V DC supply to OBC from the EMU battery Causing intermittent on-board system failure

15. CORRECTIVE ACTION Cables between CBOP and MTORE cards changed to screened twisted pair cables Power filter provided at the input of 110V DC to OBC All OBC rack wiring changed as per modification plan sent by Ansaldo, France

16. ODOMETRIC SYSTEM ERROR Interference from EMI TPWS traction control relay generating wide spectrum of noise High resistance between EMU body and the bogie

17. CORRECTIVE ACTION Cable between OBC and Speed sensor shielded with copper braids firmly connected to body TPWS traction control relay shifted outside OBC cubicle EMU body to bogie firm connection provided

18. BACK EMF FROM EB VALVE AND EP RELAY COILS EB and SB relays found affected by EMI Back EMF of EB solenoid valve coil and EP brake relay coils found high Problem became more acute during braking

19. CORRECTIVE ACTION EB solenoid valve coils terminated with 180/200V MOVRs EB & SB relay bodies firmly connected to EMU coach body Surge suppressor provided at the EP brake coil

20. BLANKING OF SDMI ON RUN Basic hardware and software inadequacies Residual bugs in SDMI software Interference from EMI Ripples in 110V DC input power supply

21. CORRECTIVE ACTION SDMI software upgraded to next higher version v1.6.4 OBC-SDMI communication cable connector cover changed from plastic to metallic OBC-SDMI and SDMI power supply cables shielded with copper braids firmly connected to coach body Power filter provided at the SDMI-110V DC input point

22. REAR COACH ON-BOARD GETTING SHUT DOWN ON RUN Due to errors in various subsystems the on-board gets shut down. On-board shutting down activates EB command

23. CORRECTIVE ACTION Brake interface circuit modified to bypass EB command in Sleep Mode. Prevent the On-Board in sleep mode from getting shut down by the modifications discussed earlier.

24. PLAN OF ACTION FOR MODIFICATIONS One by one motor coach to be taken OFF service & handed over to Ansaldo Initially 4 coaches were got modified Their performance closely monitored for 4 weeks Found substantial improvement in performance of these 4 coaches

25. PLAN OF ACTION FOR MODIFICATIONS…contd Balance coaches also decided to be modified Ansaldo initially took 3-4 days for modifying a coach Ansaldo asked to reduce it to 2 days by working in two shifts 17 coaches modified till date

26. EXPECTATIONS Most of the coaches are expected to be modified by 31.05.2010 Improved performance levels expected to meet the operational requirements Could lead to acceptance of TPWS for safe running of EMUs Top management requested to be patient for the results