Reliability improvement measures-II.

1.       Problem - Mechanical Bonded Radiator Core leakage.

          Leakages are from mostly end-tubes. Both first and last row of inner tubes near both sides are found rubbing with corner plate which results in tube puncturing. 

Action to be taken:

firm should be advised to review the design to avoid rubbing of both first and last row of inner tubes with the corner plate.  Provision of Heat Resistant Rubber pads or any suitable material in between inner tubes and the corner plate should be provided to avoid rubbing and puncturing. Dummying of these tubes should be tried. Tightening of radiator header bolts during commissioning & yearly schedule to arrest water leakages should also be done.

2.       Problem – Leakage of Fuel Oil from Fuel Header Brazing Joint & Fuel Header Block.

          There have been cases of failures due to Fuel Oil Header brazing joint leakage and Fuel Oil Header Block was having leakage.

          Brazing and hydraulic testing of the detected area should be carried out. Shop should be requested to review the design of Fuel Header and ensure strict quality control for manufacturing of this header.

3.       Problem – A/C core discharge pipe line leak

There have been cases of leakage of A/C core discharge pipe line due to ’Y’ manifold flange welding crack.

Welding and hydraulic testing of the detected area should be carried out. 

         

4.       Problem – Suction Pipe line from tank to suction trap      

There have been cases of rubbing of Suction Pipe line from tank to suction trap in lube oil strainer.

Action to be taken:  Adequate gap should be maintained or flexible hose can be used. Cases of failure should be reported to Shop along with photograph & details.

5.       Problem – Fuel oil tank bottom crack

          There have been cases of premature welding crack in the bottom of the Fuel Oil Tank leading to fuel oil leakage and posing an unsafe condition.

Action to be taken:  shop should be requested to review the design and quality of fabrication of Fuel oil Tank as attention to Fuel Tank welding becomes a major work in Running Shed. Leg has been removed in some Sheds.

6.       Problem -     Drainage of Fuel oil through Fuel tank drain plug.

The drain valve provided in the Fuel tank for drainage of fuel oil is at slightly higher level due to which complete drainage of fuel oil contaminated with water becomes difficult.  Welding joint is also found at bottom of the tank.

Action to be taken: Welding of existing joint should be checked & one round re-building should be done. shop may be advised to review the drain valve location.  In addition, the design may be reviewed for re-location of welding joint from bottom to side.

7.       Problem – Fuel oil tank cleaning

Fuel oil tank is found rusted badly in number of locomotives.  

Action to be taken:  Shed must clean the tank before commissioning the loco. shop may be advised to provide bigger size man-hole & ensure through cleaning of tank before despatch.

         

8.       Problem – Ejector assembly adopter drop      

Ejector assembly adopter comes out as only few threads of adopter are found engaged with the Ejector assembly.  

Action to be taken:  Ejector assembly thread should be re-machined and refitted. shop should be advised to ensure proper fitment of the adopter with the Ejector assembly to improve the reliability.

9.       Problem – Oil pan to inlet pipe line flange leak       

There have been cases of failures due to leakage of lube oil from oil pan to inlet pipe line flange due to poor welding.

Action to be taken: shop should be advised to ensure quality workmanship in this area. Welding quality should be checked and these should be re-welded.

10.     Problem – Centre pivot bolt broken     

There have been cases of Centre Pivot bolt breakage.

Action to be taken:  shop should be advised to review the quality of Centre pivot bolts and also to use disc lock washer if warranted. Centre pivot bolt condition should be checked in 90 days & above schedule.

         

11.     Problem – Frequent breakage of Vertical Damper holding bracket bolt

There have been large number cases of breakage of Vertical damper holding bracket bolt. 

Action to be taken:  shop should be requested to review the design and fixing arrangement to improve the reliability. Anti-seizure compound should be used during fitment of bolts.

         

12.     Problem – Rubbing of Hand-brake chain with top gear case body

The hand-brake chain arrangement is found rubbing with top gear case body & may result in gear case oil leakage leading to traction motor seizure. 

Action to be taken:  Existing old design lever type hand-brake should be replaced with new design wheel type hand-brake arrangement and also ensure adequate clearance between hand-brake chain and the top gear case should be ensured.

13.     Problem –     Non-opening of ‘H’ type CBC (centre buffer coupler)

                              Provided in WDP_4B / WDP_4D

Transition rod is not aligned properly and due to this, it is not allowing lock lifter to lift the lock.  Especially when the CBC moves away from its central position and the Operator, it is not at all able to lift the lock.

Action to be taken:  shop should be requested to ensure the alignment of the transition rod correctly and also ensure the easy opening of ‘H’ type coupler even when the CBC is at the extreme end from the central position.

14.     Problem – Chamber to crankcase gaskets given up

There have been cases of Loco Failures where the chamber to crank case gaskets have perished resulting in leakage of exhaust gases.

The gaskets received in the new locomotives turned-out from shop are of poor quality and they are failing frequently leading to exhaust gas leakage.

Action to be taken: Good quality of Gaskets (single integrated & compressed type) should be used to replace shop fitted gaskets.

         

15.     Problem – Premature failure of Tube Assembly water inlet pipe

          There have been cases of Loco failures where Tube assembly water inlet to power assembly had failed prematurely due to the circumferential crack, less thickness of tube and improper quality of manufacturing (notches, tool marks, etc.).

Action to be taken:  Proper alignment & lab testing of tube should be ensured before fitment. shop should be requested to review the design especially thickness of the tube.  Strict quality control from the Vendors is also extremely essential because this pipe gets weakened at the ends where brazing is done.

16.     Problem – Joint expansion assembly crack

          There have been cases of Joint expansion assembly crack. 

Action to be taken:  Only OEM approved joints should be fitted at vulnerable locations. shop should be requested to review the quality of indigenously manufactured Joint assembly expansion to improve the reliability.

17.     Problem – Water entering between power pack retainer to engine block

          There have been cases of water entering between power-pack retainer and engine block due to bad workmanship & Engine block crack. 

Action to be taken:  Suitable sealant should be applied at vulnerable locations. 

         

18.     Problem – MR pressure dropping

There have been cases of MR pressure dropping due to both inlet and discharge valves spring breakage.

Action to be taken:  Good quality spring should be fitted one round during 180 days & above schedules. 

19.     Problem – Compressor Dip stick flange bolt drop due to inadequate length.

Action to be taken: Diesel Shed should provide bolts of adequate length (20 mm long) with spring washer in all the locomotives. 

20.     Problem –     Defect in line assembly fuel oil manifold injector

Action to be taken:  shop  should be requested to review the specification of Cone material to avoid the damages as at present, the material is getting easily damaged. Drive during schedule should be started.