N KASHINATHCSTE/P/S.RLY

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

TPWS BENEFITSEnsures 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.

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 SignalNoteJB-Balise Junction BoxLEU-Lineside Electronic Unit Not to scale

Data Cable

OBC

BTM Brake Valves

On Board-Cubicle

Wheel Sensor

JB Wheel Sensor

JB

Antenna

ON BOARD EQUIPMENT LAYOUT DIAGRAM

OBC-On Board ComputerBTM-Balise Transmission Module

JB-Junction Box

DMI

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

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.

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

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

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

CAUSES IDENTIFIED

BTM-Antenna communication failureError in Train Interface Unit (TIU)Error in Odometric (speed sensing)

systemBack EMF from Electro Pneumatic (EP)

brake relay and solenoid valve coilsBugs in SDMI software and hardware in-

adequaciesRear coach on-board system getting shut

down during run in Sleep Mode

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

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

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

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

ODOMETRIC SYSTEM ERROR

• Interference from EMI

• TPWS traction control relay generating wide spectrum of noise

• High resistance between EMU body and the bogie

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

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

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

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

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

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

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.

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

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

EXPECTATIONSMost 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