Additional Troubleshooting for WAP-7 Locomotives Working with HOG

13 Sep 2026
South Eastern Railway

Office of the Pr. Chief Electrical Engineer

41, Garden Reach, Kolkata-43

No. PCEE/RS/268/Misc./26/105 | Date: As signed

⚠️ Additional Troubleshooting for WAP-7 Locomotives Working with HOG

Ref.: OPR of Loco No. 39224/WAP-7/SRCE dated 01.09.2026

Issued to: Sr. DEE/OP/KGP, CKP, ADRA & RNC

1. Reported HOG Failures

WAP-7 locomotives working in HOG mode with power cars have experienced failures due to tripping of the following control circuit MCBs:

127.7 Brake Electronics
Brake Electronics Circuit Breaker
127.81 & 127.82 Commissioning
Commissioning Circuit Breakers
127.2/1 & 127.2/2 Monitoring
Monitoring Circuit Breakers
129.2/1-1 HOG
Hotel Load Circuit Breaker
2. Indications Observed

In many cases, the following indications have been logged despite MR pressure being available and within normal limits:

“Brake Electronics Failed”
“MR Pressure Low”
3. Additional Troubleshooting Procedure
Recommended Action
  1. In the event of the above failures, disconnect the HOG UIC coupler once.
  2. Re-check the locomotive after disconnecting the HOG UIC coupler.
  3. Check whether the reported trouble recurs.
Important: Disconnecting the HOG UIC coupler has resulted in the locomotive functioning normally in reported cases.
4. Failure Case – Loco No. 39224/WAP-7/SRCE
Train
22841 (SRC–TBM)
Date of Failure
01.09.2026
Location
GPT–VSKP Section
Load
21 LHB Coaches
Propulsion
IGBT Medha
Brake System
E70
Failure: VCB tripping with auto application of brakes occurred, with MR and BP pressures dropping.

MCB 127.7 in the SB-2 panel was found tripped and could not initially be reset. After battery OFF/ON, MCB 127.7 reset, but tripped again when the battery was switched ON.

DDU Fault Message:
F1001P1 – “Brake Electronics Failed, Emergency Brakes Applied and No Traction Allowed”
5. Investigation Findings
  • MCB 127.7 and MCB 129.2/1-1 (HOG) were found in tripped condition.
  • Pneumatic testing of both cabs was found normal after making MCB 127.7 normal.
  • An earth fault in the battery circuit was logged when the locomotive was made live.
  • HLC2 lamp glowing without jig indicated a positive earth fault in the locomotive.
  • Positive cables 16B and 57A in the pneumatic panel were found pressed and punctured at the snubber circuit PCB board.
  • Cab-1 LP-side HOG IV coupler cap short link plate for pin numbers 7 & 10 was found earthed, causing positive earth fault of HOG.
  • Cab-2 LP IV coupler cables were found pressed with insulation damage, causing positive earth fault of HOG.
6. VCU Faults Logged
Fault Code Fault Description
F0905P2 MCC: Earth Fault in Battery Circuit
F1005P1 MCC: S/R Interlock – Auto Brake
F1002P1 MCC: S/R Interlock – Main Res Low
F0103P1 MCC: Low Panto Pressure – VCB Off
F1001P1 MCC: Brake Electronics Failed
F0103P1 MCC: No Pressure in Panto 2
F0106P2 MCC: AFL Activated
7. HOG Power Car Investigation

Joint checking was carried out at VSKP with Loco No. 37200/BZA and Power Car No. 138853.

Finding: After removing the UIC, the B-side fixed coupler Pin No. 12 of Power Car No. 138853 was found permanently earthed (-ve).

The loco display showed an earth fault, which disappeared after removing the UIC.

8. Cause of Failure
Positive earth fault in the locomotive and negative earth fault associated with HOG Power Car No. 138853 resulted in tripping of MCB 127.7 (Brake Electronics Circuit), causing the “Brake Electronics Failed” indication.
9. Equipment Details
Brake System
FTIL
Under Warranty
Power Car UIC Fixed Coupler
Pin No. 12 – Earthed
10. Responsibility
Primary
Carriage & Wagon
Traffic / wrongly logged
Secondary
Brake Panel – FTIL
11. Action Taken / Action Plan
  1. Complete implementation of RDSO MS-488, Rev.1 dated 12.03.2026 in all HOG locomotives.
  2. Carry out one-cycle checking of all cables and connectors of the E70 brake system.
12. Guidance for Loco Crew / TLC
In case of the specified HOG-related failure: disconnect the HOG UIC coupler once and re-check the locomotive for recurrence of the trouble. Concerned LIs and TLCs should guide the crew accordingly as an additional troubleshooting procedure.

Chief Electrical Loco Engineer

South Eastern Railway


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