RAIL TECHNOLOGIES

RAIL TECHNOLOGIES

BOBRN maintenance & problems and their solutions


MAINTENANCE RELATED PROBLEMS OF  BOBR / BOBRN WAGONS AND THEIR SOLUTIONS ”

MAJOR COMPONENT DEFECTS NOTICED DURING MAINTENANCE
  • Breakage of adjustable bushing lug.
  • Breakage of adjustable lever lug.
  • Breakage of door hinges.
  • Bent or broken eye bolts.
  • Door clips bent and its hole elongated.
  • Corrosion of door lips.
  • Breakage of bronze bush.
  • Working out of clevis of turn buckle.
  • Breakage of DOM air cylinder barrel.
  • Grazing of SAB pull rod with door operating connecting rod.
  • Grazing of  turn buckle with door operating shaft.
MAJOR DEFICIENCIES NOTICED DURING POH / NPOH
MAINTENANCE RELATED PROBLEMS
  • The BOBR/BOBRN type wagons are maintenance intensive due to higher rate of failures of components and sub assemblies  of door operating mechanism
  • Maintenance cost is relatively high in comparison to that of other type of wagons due to higher failure rate   and longer repair and maintenance time
  • Lack of easy accessibility and replaceability of components and sub assemblies  prone to frequent failure
  • Effect of operating environment leading to corrosion problems
AREA WISE MAINTENANCE PROBLEMS

WORKING OF THE DOOR OPERATING MECHANISM


DOOR OPERATING MECHANISM
Replacement of adjustable bushing complete for breakage of lug.
  • Dismantling of the full unit ( square shaft, adjustable bushing assembly, bronze bush bearing assembly ) from the wagon by removing the pins and cutting the  rivets.

OXY CUTTING  THE RIBS IN BETWEEN THE LEVER PLATES.


REMOVAL OF THE BROKEN ADJUSTABLE  BUSHING .


FITMENT OF  NEW/SERVICEABLE ADJUSTABLE BUSHING IN THE ASSEMBLY AND WELDING THE RIB.


MOUNTING OF THE ASSEMBLED ADJUSTABLE BUSHING ON THE CENTER SILL OF THE WAGON


  • Changing of adjustable bushing is maintenance intensive which requires more time and man power.
REPLACEMENT OF BROKEN BRONZE BUSHES.
Dismantling of bronze bush bearing assembly by oxy cutting lug and stoppers from the square shaft

REMOVAL OF THE BROKEN BRONZE BUSH FROM BEARING HOUSING.

ASSEMBLING THE NEW/ SERVICEABLE BRONZE BUSH IN THE BEARING HOUSING AND MOUNTING THE SQUARE SHAFT .
RIVETING THE BRONZE BUSH BEARING ASSEMBLY ON THE CENTRE SILL OF THE WAGON AND WELDING  THE STOPPER
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  • Changing of bronze  bush is maintenance intensive which requires more time and man power

BUSH ECCENTRICITY


BREAKING OF HINGES


WORKING OUT OF SAB PULL ROD 


WORKING OUT OF SAB PULL ROD 

GRAZING OF TURN BUCKLE

ADJUSTMENT OF DOOR OPERATING MECHANISM

Door operating lever correctly adjusted.

      No gap in X and Y end and gap of 0 to 5 mm on one side and no gap on   
       the other side in the central door connecting links.

ADJUSTMENT OF GAP BETWEEN ADJUSTABLE BUSHING LUG AND LEVER LUG
Gap of 14 mm + 5 mm to be maintained  at either end and in central location


ADJUSTMENT OF TURN BUCKLE AND ITS LOCKING
Turn buckle to be properly locked by adjustable bolt after correct adjustment .


SECONDARY LOCK ADJUSTMENT

  • Secondary lock Clarence -  6 to 10 mm gap under air pressure and 0 to 2 mm gap when air is released .


ADJUSTMENT  AND LOCKING OF EYE BOLT


OVERHAULING OF DOM AIR CYLINDER

  • Types of DOM Air Cylinder – 14” & 12”
  • Difference between 14” & 12” DOM Air Cylinder

Component Particulars
14” Cylinder
12” Cylinder
Barrel length
578 mm
630 mm
Piston Dia.
355 mm
305 mm
Piston Rod length
775 mm
870 mm
Stroke length
508 mm
560 mm

There are four  types of DOM Air  Cylinders.
Make wise in service  
1 Hydrodyne Pneumat Pvt. Ltd.
2 Techno Chem Pneumatics Pvt. Ltd.
3 Nucon Industries Pvt. Ltd.
4 Pioneer Engineering Works
The Components of the DOM air Cylinders of different make are not
interchangeable .

AIR CYLINDER IN USE BARRELS  OF DOM



DOM AIR CYLINDER END COVERS

DOM AIR CYLINDERS PISTON

DOM AIR CYLINDER PISTON ROD


DEFECTS NOTICED IN PISTON ROD
The DOM Air Cylinder repair kits     (Rubber items) manufacturer wise   are different which calls for  stocking four different types of   repair kits.

CORROSION / DAMAGE OF DOOR LIPS.



REPLACEMENT OF THE DOOR DUE TO HEAVILY CORRODED DOOR LIPS
  • Dropping   of the complete door assembly from wagon  by removing the hinge pins and eye  bolts.
  • Fitment of new door complete

   
Dropping and refitment of complete door assembly from and to the wagon is  quite cumbersome due to heaviness of  the door assembly and limited space available underneath the wagon .

SOLUTIONS  SUGGESTED
Expeditious implementation of Design   Modifications suggested by RDSO during manufacturing , POH & ROH

  • Adjustable bushing.
  • Lever top lug.
  • Turned buckle clevis.
  • Door plate.
  • Hopper plate.
  • Clevis locking plate.
  • Door hinges.
DESIGN OF COMPONENT TO BE REVIEWED
  • Man operating lever bushing
  • Bronze bush
  • Door clips
  • Additional support for pull rod at SAB end

OTHER  SUGGESTIONS

Ø      Bad workmanship during manufacturing stage should be eliminated .
Ø      DOM air cylinder and its repair kit should be standardized .
Ø      Maintenances instructions for overhauling of DOM air cylinder with list of must change items to be prepared by RDSO for implementation in the work shop.
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