CnW Maintenance Manual PDF

CHAPTER 8-DRAW AND BUFFING GEAR Page 1 of 38 CHAPTER 8 DRAW AND BUFFING GEAR 801. GENERAL There are two main arrangements of draft and buffing gear in use on Broad Gauge. The olde...

CHAPTER 8-DRAW AND BUFFING GEAR Page 1 of 38 CHAPTER 8 DRAW AND BUFFING GEAR 801. GENERAL There are two main arrangements of draft and buffing gear in use on Broad Gauge. The older arrangement, which is found on few wagons, consists of a screw coupling with side buffers. In this design the draft load is transmitted through the screw coupling, draw hook and draw hook springs while the buffing force is borne by the side buffers. The conventional screw coupling (WA/BD-125) has a working load of 22.5t. The restrictions of size and weight limit the extent to which the draft capacity of this coupling can be improved. Recognizing this fact, the other arrangement on BG wagons is that of a Centre Buffer Coupler (CBC) which transmits both draft and buffing loads. The knuckle type centre buffer coupler was adopted for BOX, BOXN and other new design of wagons. Later on, a smaller knuckle type coupler, known as the Alliance-II coupler, was introduced for four wheeler wagons. The working strength of CBC and Alliance-II coupler is 120 tonnes and 54 tonnes respectively. CBC also has a transition version called “Transition Coupler” which incorporates a screw coupling and a pair of side buffers to permit attachment with wagons fitted with screw coupling. The conventional Draw and Buffing gear have been phased out hence details of these have not been included in this manual. Since now-a-days, high capacity Centre Buffer Coupler (CBC) and Draft Gear are used on BG freight stock, paras 802 to 810 have been deleted. For maintenance of draw and buffing gear 2002 version of this manual should be referred. 802. CENTRE BUFFER COUPLER & DRAFT GEAR A) Indian Railway uses AAR type centre buffer couplers having E-type head and F-type shank for freight stock on Broad Gauge system. These couplers are generally as per requirements of AAR specifications M-201, M-205 and M- 211. The upgraded indigenous CBCs(UHTE) as per RDSO specs. No. WD- 70-BD-10 are also being fitted in the wagons. B) The draft capacity of the AAR coupler depends on the strength of knuckle, which is weakest link in the assembly. The yield strength of knuckle of material AAR M-201 Grade `C' & Grade `E' is 132 t and 180 t respectively. C) ADVANTAGES OF AAR CENTRE BUFFER COUPLER  Coupler and buffing gear are both located together at the centre of the wagon.  Centre buffer coupler is identical at either end of the wagon and hence wagon direction is immaterial.  Coupling action between wagons is automatic.  With transition arrangement, coupling with screw coupling is possible. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 2 of 38 803. PARTS OF CENTRE BUFFER COUPLER ASSEMBLY The main parts of Centre Buffer Coupler are as under:- i) Coupler body ii) Knuckle iii) Knuckle pivot pin with washer iv) Lock v) Knuckle thrower vi) Toggle vii) Universal lock lift lever connector viii) Lock lift lever hook ix) Lock lift rivet x) Lock lift lever rivet xi) Top lifter hole cap xii) Yoke pin xiii) Yoke xiv) Yoke pin support. xv) Striker casting xvi) Striker casting wear plate xvii) Shank wear plate xviii) Yoke support plate xix) Draft Gear arrangement with front follower xx) Safety bracket with anchor plate xxi) Uncoupling gear arrangement xxii) Back stop xxiii) Clevis for Transition type coupler only xxiv) Screw coupling for Transition type coupler only xxv) Clevis pin for transition type coupler only All parts of non-transition coupler are identical and therefore inter- changeable with those of the transition type coupler except striker casting with wear plate and coupler body with shank. In transition CBC coupler body with shank is longer and is provided with an arrangement to fit clevis with the help of clevis pin. 804. INSPECTION OF CBC A) Coupler and operating mechanism: When inspection of coupler and coupler operating mechanism is made, it is important to check when the coupler operating mechanism is operated to fully open the knuckle, and the knuckle is slowly closed, the lock drops freely and the mechanism returns to fully locked position. The lock position is indicated by the toggle, which is clearly visible below the coupler head. B) Only dry lubricant shall be applied to the coupler head or the coupler head fittings. This lubricant may be applied using water, alcohol, or other non- petroleum based carrier. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 3 of 38 WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 4 of 38 C) Only exposed surfaces of Coupler and Yoke shall be painted with Black quick drying paint in accordance with IRS R6. Paint must be applied to the inside of the Coupler or internal fittings. Painting shall be done after the completion of inspection of Coupler & Yoke of acceptable casting lot. D) When in the transition Centre Buffer Coupler, the knuckle does not move freely, grind the top face of "top pulling lug" and "lock face" of knuckle in position. If still not free, remove knuckle and clean "pin protector guides" on coupler head. If, after attending to knuckle, the lock still does not fall, remove the lock and grind “locking face knuckle side” on lock so that the lock falls freely. E) Inspection of couplers, whilst fitted to wagons, should be made to ensure proper coupling any position which it can assume during train operation. The procedure is as follows:- a. Check correct operation in order to ascertain that full knuckle throw, lock set, lock-to-lock (anti-creep) and locking is obtained. If any of these functions be unsatisfactory, they should be corrected by replacing the defective components. b. Check that the shank is not bent out of alignment with the head. If defective, the coupler shall be removed for straightening of shank. c. Examine shank wear plates (when fitted) and if worn through, the couplers shall be removed for fitting of new plates. Examine wear on shank (when wear plates not fitted) and if wear is approaching 6.5 mm (1/4"), the coupler shall be removed for building up of shank by welding. d. Examine head for cracks in the knuckle side wall. If cracked, the coupler shall be removed. e. Check the distance between the nose of the knuckle and the guard arm with gauge No. 1. If it passes (which is 5.5/16" long), it indicates that the coupler has its condemning limit. In such a case the knuckle pivot pin, lock etc. should be replaced so that gauge No.2 does not pass. If this gauge passes, then the coupler should be removed. f. Examine the operating mechanism. If defective or deficient, the defective or deficient components should be replaced to ensure free movement. g. Check knuckle pin & clevis pin to ensure that pin of correct size has been used. Check fastening arrangement of knuckle pin and clevis pin. The former has a welded washer while the later has a riveted head over a washer in position. h. Coupler height should be checked in accordance with IRCA Part III Rule No. 2.13.7. i. All defective/deficient components shall be replaced in CBC, clevis and screw coupling (in case of transition couplers). 805. INSPECTION OF DRAFT GEARS (MK-50 & RF-361) A. Excessive slack in draft gears is not permitted and this should be either reduced or eliminated. The maximum permissible free slack in the draft gear is 25 mm(1") after which, it shall be removed and reclaimed or condemned. The free slack can be determined by first sledging the coupler back solid and then measuring the clearance between the coupler horn and the striker face. Next by inserting a long bar between the horn and striker face, pry coupler out WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 5 of 38 as far as possible and again measure the space between the horn and the striker. The difference between these two measurements is the amount of free slack. B. Visual examination of the rubber pads & coil springs when the draft gear is in place in the wagon can be misleading and the draft gears shall therefore be inspected at every POH of the wagon, irrespective of the amount of free slack existing. C. BOXN-HL and BCN-HL wagons are equipped with high capacity draft gears like “MINER SL-76 Draft Gears” etc. to RDSO specification No. WD-665-BD-06. 806. REMOVAL OF COUPLER AND DRAFT GEAR FROM WAGON A) Remove yoke pin support plate by conventional methods. Then remove the yoke pin. If necessary by inserting two chisels where the front follower bears hard against striker casting at the draft lugs. B) The coupler will now be loose and can be pulled out. Care must be taken to avoid personal injury as the coupler weighs over 200 Kg. and its head is heavier than the shank. C) Remove the yoke support plate by conventional means When the gear is loose in the wagon pocket, the gear and yoke assembly must be supported by jacks or other means to avoid personal injury. D) To remove the gear and yoke assembly when the gear is tight in the wagon pocket, first apply cross key through front of yoke and position in yoke pinhole. Then apply screw B in cross key A and turn until contact is made with front follower of draft gear. With wrench C, turn screw with the aid of a piece of 38 mm (1 1/2") pipe until gear is loose in the wagon pocket. Remove wrench and lower the gear and yoke assembly on supports from the wagon pocket. B C CROSS KEY 'A' FIG. 8.39.3 Fig. REMOVAL OF DRAFT GEAR FROM WAGONS REMOVAL OF DRAFT GEAR FROM WAGONS WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 6 of 38 E) To remove the draft gear from the yoke, compress the gear by means of screw and insert two pre-shortners as done during assembly. Then release the screw and remove draft gear. 807. CBC MEASURING GAUGES AND THEIR APPLICATIONS Contour Gauge No. 01 is used for checking of wear in guard arm and knuckle face of CBC. All wagons coming for ROH or POH are checked by this “not go” gauge A CHECKING OF GUARD ARM EXPANSION GAUGE NO. 1  Apply the gauge no. 1 as shown.  If gauge no. 1 passes, renew 1) Knuckle 2) Knuckle pin 3) Lock GAUGE NO. 2  After replacing the above, if gauge no. 2 passes, renew the coupler body.  Reason - Guard arm expanded. WAGON MAINTENANCE MANUAL  CHAPTER 8-DRAW AND BUFFING GEAR Page 7 of 38. Contour Gauge No.02 is used at outgoing wagon after repair in CBC unit. This gauge should not pass while putting between guard arm & knuckle. B CHECKING OF GUARD ARM DISTORTION  Guard Arm Gauge No.3 A C  Apply the gauge no. 3 as shown above. When „A‟ is in contact, if „B‟ or „C‟ touches, renew the coupler body.  Reason : Guard arm distorted.  Note: If guard arm distortion is more than 4.8 mm, it should be closed into normal.   Contour gauge-3 “Go and No Go type” for inspection in assembled condition WAGON MAINTENANCE MANUAL  CHAPTER 8-DRAW AND BUFFING GEAR Page 8 of 38 C CHECKING OF STRETCHED KNUCKLE KNUCKLE D A B C  Apply the gauge no. 4 as shown above.  When A,B,C are in contact, there must be a clear gap at „D‟  Application of Knuckle stretch and Nose wear gauge KNUCKLE D A B C  If „D” touches, renew the knuckle.  Reason – Knuckle is stretched. WAGON MAINTENANCE MANUAL  CHAPTER 8-DRAW AND BUFFING GEAR Page 9 of 38 D CHECKING THE KNUCKLE NOSE WEAR KNUCKLE H F E G  Apply the gauge no. 4 as shown above.  When E, F, G are in contact, „E‟ must not pass. KNUC KLE H F E G  If „E‟ passes, renew the knuckle.  Reason – Excessive knuckle nose wear.  Application of Knuckle pivot gauge _GO Drg No.- 84073-47-RC WAGON MAINTENANCE MANUAL  CHAPTER 8-DRAW AND BUFFING GEAR Page 10 of 38 E CHECKING THE KNUCKLE LOCKING FACE Gauge No.5   Locking  Face  Apply the gauge no. 5 as shown above.  The gauge must not pass through vertically.  If passes, renew the knuckle.  Reason : Excessive wear at locking face of the Knuckle.\  Application of Knuckle Profile gauge Gauge No. 05 WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 11 of 38 F CHECKING OF ANTI-CREEP LEDGE OF BOTTOM LIFTER  Apply the gauge no. 6 as shown above.  There should not be any clearance between gauge and bottom lifter.  If there is a gap, renew the bottom lifter.  Reason : Ineffective anti –creep  Application of Bottom anti-creep horizontal location gauge Drg no.- WD-84073-S- 3-RC WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 12 of 38 G CHECKING OF ANTI-CREEP LUG OF ROTARY LEVER  Gauge  No.7  Apply the gauge no. 7 as shown above.  If gauge is not mating properly with the anti –creep lug (bridge) of rotary lever , renew the rotary lever.  Reason : Ineffective anti -creep WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 13 of 38 H CHECKING OF LOCK WEAR CHECKING OF LOCK WEAR  Gauge No.8  A   Contacting   Engagement surface with  surface with knuckle coupler body   Apply the gauge no. 8 as shown above.  When the surface „A‟ is in contact, if the gap is more than 3.2 mm at „B‟ , renew the lock.  Reason : There is a combined wear of lock at knuckle contacting surface & engagement surface with coupler body. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 14 of 38 I. CHECKING OF SHANK LENGTH Shank length gauge Drg. No. WD-84073-S-22 –RC: Shank length is checked by this gauge J.CHECKING OF SHANK HEIGHT WITH WEAR PLATE GAUGE Shank height with wear plate gauge “Go” Drg No.-84073-S-21-RC: Shank height with wear plate gauge No Go Drg No.-84073-S-21-RC: Shank height is checked with the help of this gauge WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 15 of 38 K.CHECKING OF SHANK HEIGHT WITH WEAR PLATE GAUGE Shank wear gauge: wear in the plate is checked with this gauge L.CHECKING OF KNUCKLE PIN HOLE Knuckle pin hole gauge Drg. No.WD-84073-S-47-RC “No Go type”: Pin hole is checked by this gauge for wear limit Knuckle pin hole gauge Drg. No. WD-84073-S-47-RC “No Go type” WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 16 of 38 M. CHECKING OF PIVOT LUG Pivot Lug gauge No Go Pivot Lug gauge Go N.CHECKING OF PIVOT PIN Pivot pin gauge Drg No.- 84073-S-8-RC Pivot pin gauge Drg No.- 84073-S-8-RC WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 17 of 38 O.CHECKING OF KNUCKLE PIN PROTECTION Pin protector gauge- Drg. No. WD-84073 S-21-RC Knuckle pin hole protection limit is checked with the help of this gauge to avoid breakage of WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 18 of 38 808. DEVELOPMENT OF HIGH TENSILE COUPLER & HIGH CAPACITY DRAFT GEAR On BG system, to minimize the maintenance problem and to run heavy hauled freight train, the existing grade `C' type coupler have been replaced to grade `E' type coupler known as high tensile coupler. A comparative chart of grade `C' and grade `E' coupler is given below: Material Ultimate Yield strength AAR M-201 & Tensile strength ( in tonnes) AAR M-211 (in tonnes) STD. HT. STD. HT. STD. HT. Coupler body Gr.B Gr.E 290 408 169 205 Knuckle. Gr.C Gr.E 251 295 132 180 Standard CBC and high tensile CBC are identical in dimension hence no problem to couple each other. Draft capacity of the high tensile coupler also depends on the weakest link i.e. knuckle. The yield strength of the knuckle is 180t compared to 132t in standard coupler. The draft capacity of HT coupler is 36% higher. The standard draft gears are to be replaced by high capacity draft gears vide Rly. Board`s letter No.84/M(N)/172/3 Vol. I dt. 11.1.90 and 84/M(N)/172/3 dt. 5.7.90. And new freight stocks would be fitted with high capacity draft gears. At present three types of high capacity draft gears are in service  MK-50  RF-361  MINER SL-76 to RDSO specification No. WD-665-BD-06. A. COUPLER i. All bogie wagons manufactured prior to 1984-85 were fitted with HR-40-I or MF-400-I - IR draft gears but during shop schedules these are being replaced with high capacity draft gears progressively. ii. At present new freight stock are fitted with high capacity draft gear i.e. RF-361 , MK-50 & MINER SL-76. B. DESIGN FEATURES OF HIGH CAPACITY DRAFT GEARS Type Wt. Capacity Travel Reaction Performance Energy of Draft (kg) (kg.m.) (mm) force efficiency absorption Gear (tonnes) (%) (%) MK-50 170.3 5385 81.5 269.0 23.7 86 RF-361 138.0 5725 67.8 232.3 36.6 79.6 WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 19 of 38 809. RF-361 DRAFT GEAR This type of draft gear is a fully enclosed, self-contained unit assembled with pre- compression force of rubber pads, so that all parts are tight in relation to one another. Under normal service condition the draft gear is tightly fitted in yoke with front follower plate. Note :- All the drawing no., part no. and gauge no. mentioned here under are as per literature of Burn Standard Co. Ltd., Howrah Works, titled “INSPECTION AND MAINTENANCE MANUAL FOR HIGH CAPACITY DRAFT GEAR RF-361” A. COMPONENTS OF RF-361 DRAFT GEAR  Housing (cylinder)  Wedge  Shoes 3 nos  Bore inserts  Top follower  Rubber pads (Elastomer unit)  Rear wall plate FIG. 8.5:: RF- Fig. 9.6 RF - 361 361DRAFT GEAR DRAFT GEAR WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 20 of 38 B. LIST OF GAUGES FOR RF-361 DRAFT GEAR a. Gauges for housing:  Gauge - 27200 Profile gauge.  Gauge _ 27706  Gauge _ 27257 Flatness gauge.  Gauge _ 27244 Height gauge ( GO & NO-GO) b. Gauges for Shoes  Gauge - 27253  Gauge _ 27254  Gauge _ 27298  Gauge _ 27716 c. Gauges for Wedge  Gauge - 27215  Gauge _ 27216  Gauge _ 27266  Gauge _ 27267 d. Final Inspection gauges  Gauge - 27207 - Pre-shortened assembled gauge  Gauge - 27739 - Box gauge C. MAINTENANCE a. The RF-361 draft gear will require complete reconditioning, i.e. removal and replacement of the rear wall plate only if the gear has loosed clutch components (shoes & wedges), a broken housing, or a cracked weld at the rear wall. I. A loose clutch will normally mean that there is either a defective rubber springs package or excessive wear has taken place on the cylinder bore friction surfaces. With a loose clutch, the steel components will usually be moved by hand. II. A cracked weld indicates poor welding practice during initial assembly causing a fatigue crack, or brittle weld which can fail under extremely high shocks loading etc. III. If a loose clutch, broken housing, or a cracked weld are not present then only removal and replacement of clutch components is necessary. Normally, clutch disassembly and replacement is the only reconditioning needed in the RF-361 draft gear. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 21 of 38 b. DISASSEMBLY PROCEDURE FOR RF-361 DRAFT GEAR If either the shoes or wedge are broken and clutch is not loose, the following disassembly procedure can be used to replace the broken components. (I) The following equipment & special tools will be required to remove the shoes and wedge from the draft gear; i. 200 tonnes vertical open gap press ii. Assembly block Drg. No.27051 iii. Assembly Ring iv. A wooden taper wedge plug for the old style hollow wedge or a 76 mm or 3" diameter industrial strength magnet with special long handle for the new solid wedge. (II) The press should be equipped with an appropriate ram press head to drg. no 27800 to facilitate removal operations. III. Place the assembly ring over the top outside of the friction bore of the cylinder. Put the assembly block inside the assembly ring so that its three slegs evenly contact the three shoes. Place the magnet on top of the solid wedge, its handle protruding through the hole in the assembly block. IV. Press down the assembly block compressing the shoes slowly into the gear. While continuing to press on the shoes grasps the magnet or wooden plug handle and rotate the wedge clockwise until the wedge lugs are completely clear of the housing lugs. The top of the shoes need to be almost even with the bottom of the housing lugs before the rotation can be accomplished. Once the lugs are clear to each other compression can be released and wedge and shoes can be removed. c. INSPECTION OF COMPONENTS I. SHOES The shoe, which have to be reused must be free from the following defects.  No concave wear on any friction surface  No cracks or spalls  No wear more than 0.8 mm or 1/32" on any friction surface II. WEDGE The wedges which have to be re-used must be free from the following defects. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 22 of 38  No crack or spall of the carburized case on the friction faces or the top of the wedge.  No wear more than 0.8 mm or 1/32" on the friction surface.  No indication of broken or any cracks on any of the locking lugs. III. HOUSING OR CYLINDERS  The inside friction bore walls must be worn symmetrical and the wall thickness must not be less than 20.6 mm or 13/16"  There must not be any bottom ridging in the bore.  Bore taper should be smooth and any concavity must not be exceed 0.8 mm or 1/32". There should not be broken lugs or cracks in the housing.  The housing should not be bulged outside.  The housing must pass through profile gauges No. 27706 and 27200.  Housing base flatness must meet gauge No. 27257. IV. To function properly, every part of the assembly must be free of oil, grease and moisture. The parts should be kept properly during storage, handling and re-assembly. V. Wedge and shoes are to be shot-peened to remove rust and dirt before assembly. Shot-peening also allows better visual examination. No sharp edges are to be permitted on these parts, since they could cause cutting and gouging. VI. For re-assembly, the assembly ring is first placed over the housing. The three shoes are put into position in the bore, and the wedge (with magnet placed over the shoes) with each wedge lug resting on the angled shoulder of a shoe. Next, the assembly block is put over the wedge carefully, pushing the shoes into the housing. When the top of the wedge lug has cleared the bottom of the housing lug, clockwise, the wedge will fall into place and the compression can be released, completing the assembly. D. COMPLETE RECONDITIONING a. If complete reconditioning of the gear is required either because of a loose clutch or a broken weld, the shoes and wedge must be removed from the gear in the manner that has been described above. This reduces the internal spring force of the gear stated above. b. The rear wall plate must be removed from the gear housing for complete dis-assembly. The gear should be mounted in a holding fixture incorporating a hydraulic press acting axially on the housing ends. Lock the hydraulic ram about ¼” (6 mm) longer than the housing length so that WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 23 of 38 the rear plate will be able to separate from the housing during cutting. The press ram must be capable of resisting a force of 10 tons exerted by the rubber pad spring stack. c. Cutting of the rear wall plate can be done by an abrasive cut-off wheel, sawing or flame cutting. Make the cut just less than the 1 ¼” (32 mm) thickness of the rear wall plate. NOTE If the flame cutting is used, adequate ventilation and air movement during the cutting must be provided. If there is a shortage of air during rubber burning, the rubber pyrolysis could create an explosive mixture. d. Release the hydraulic ram to free the gear. Remove the rubber pads and internal follower from the housing. e. Inspect the housing and also the housing wall thickness at the bottom which must not be less than 11.9mm (or 15/32") and 19.8mm ( or 25/32") respectively. f. Inspection of Rubber pads I. Reject pads which show tears, large material chunks, large bond failures, or extreme wear into the steel plate edges. II. Pads are gauged and must not be less than 2 1/8” (54 mm) as measured by a gap gauge at the middle of each side. III. Bent (but not broken or cracked) steel plates are acceptable as these will straighten during assembly. IV. Creases and folds are normal and are acceptable for reconditioned gears. V. VISUAL INSPECTION OF RUBBER PADS i. Full bonding to each of the metal is required. ii. Top and bottom surfaces of plates must be free of elastomer films or drops. iii. Inspection sprues must be 3.18 mm or 1/8" min. below the steel plate surface. iv. Pad must be free from cracks. v. Parting line flash should not exceed 0.78mm or 1/16". vi. Elastomeric material should be free from foreign material i.e., trapped air etc. vii. Check for proper markings. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 24 of 38 VI. STATIC TEST i. Rubber pads must be inspected carefully. Hundred percent pads are inspected visually. Squeeze each pad to a height of 37 mm and check for bond failure, chunks cracks and bubbles. These defects are causes for rejection. ii. Check pads for bulge. Elastomer should not extend beyond the steel plates when squeezed to solid height. iii. Pad must be returned to minimum free height of 61 mm within one minute after load is released. iv. Pads must not be skewed after the load is released. g. INSPECTION OF INTERNAL FOLLOWER I. Outside profile dimension must be at least 111/4” x 7” (286mmx178 mm). II. Base must be flat within 1/16” (1.6mm) across the diagonals. III. Base and show support boss must be parallel within 1/16” (1.6mm). IV. Shoe wear indentations on the boss must not exceed 1/16” (1.6 mm). h. INSPECTION OF FORGED ITEMS I. Parts will be visually inspected for seams laps, scale pits, improper grinding and other defects. II. All items should be checked for proper and distinct markings which should be legible. III. Parts are to be gauged for dimensional checking. IV. Some dimensions are checked with calipers scales or other measuring instruments as required if gauges do not exist or not available. i. INSPECTION OF HOUSINGS (CYLINDERS) I. Housings or cylinders must not have excessive porosity, surface discontinues shrinkage and inclusions. II. proper gauges should be used to ensure sufficient yoke clearance and for checking rear wall flatness. j. PREPARATION OF HOUSING PRIOR TO RE-ASSEMBLY I. The housing is placed bore end down on a flat metal work table next to a flame cutting fixture. An accurate flame cut may be achieved by using either a guided torch nozzle which moves along the stationary housing length at a fixed height, or by moving the housing past a fixed torch nozzle. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 25 of 38 II. The housing is to be cut to a length of 463.6 mm  1.6 mm (18 ¼”  1/16”). It is important to regularly clean the torch tip to help ensure a clean and accurate cut. III. After each side is cut, the housing is hit with a hammer to remove slag. The work table and guides should be swept clean of slag after each cut to ensure a level cutting surface and proper height position for the following cuts. The housing can be rotated by hand before cutting on a new side. IV. Check the finished housing (cylinder) height using gage no 27244. V. Grind after cutting with a hand grinder to; Remove flame cutting marks back to clean steel Remove slag deposits on the housing Bring correct size to the finished length. E. RE-ASSEMBLY OF RE-CONDITIONED RF-361 DRAFT GEAR a. Tools required  50 t vertical press  Draft Gear assembly ring support fixture. b. For re-assembly, the assembly ring is first placed over the housing. The three shoes are put in position in the bore and the wedge is placed over the shoes, with each wedge lugs resting on the angled shoulder of the shoes. Next, the assembly block to drg. No.27051 is put over the wedge, so the legs of the assembly block contact the top of the shoes. Press down very slowly and carefully, pushing the shoes into the housings. When the top of the wedge has cleared the bottom of the housing lugs either by tapping the handle or slightly rotating it clock- wise, the wedge will take its position in place and the compression can be released. F. INSPECTION OF RECONDITIONED DRAFT GEARS RF-361 Draft gear shall be visually inspected for the following characteristics:-  Inserts - one insert per lug properly located and intact in position.  Shoes - must be properly positioned with respect to the wedge.  Housing - must be free from cracks lumps and other defects. Components must be properly seated. Clutch components must be tight. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 26 of 38 G. WELDING OF REAR PLATE AFTER ASSEMBLY a. After the weld zones of the housing and rear wall plate have been suitably preheated, the heating gas is to be turned off, and the heating ring is to be removed from the housing. b. Place the remaining two RF-8 rubber pads on the pad stack These pads will be projecting above the rear of the housing. c. Place the preheated rear wall plate on top of the rubber stack and position it as closely as possible so the edges of the plate align with the edges of the housing. d. Position on draft gear assembly so that it is centered directly under the ram of the press (50 tonne vertical press). This is done to ensure even loading and square closure. e. Compress the rear wall plate down until it is firmly and squarely in contact with the housing base. Check the alignment of the rear wall plate sides in relation to the housing base sides. If necessary, release the press pressure, reposition the plate and compress again until the sides of the two pieces are aligned. It may be necessary to do this a number of times, depending on the skill and experience of the operator, till the proper alignment is obtained. H. ROOT RUN WELDING a. With the rear wall plate firmly held in place under the press, a root run, approximately 6.4 mm-7.9 mm (1/4"-5/16") in depth is made completely around all four sides. It is very important to obtain complete fusion and penetration into the full depth of the weld preparation. b. MIG welding with AWS A5.18-69 class E70S-1B, 1.14 mm (0.45”) diameter, 100,000 psi tensile wire is used. Preferable shielding is a 75% Argon and 25% CO2 gas. Wire feed speed is 45.7-50.8 cm (18-20 inches) per minute and the welding machine to be set for 250 - 280 amps. 26-32 volts. c. When the root run has been completed, the gear is removed from the press and moved aside. Inspect, to be sure that it is free of any visible defects. A total of three to four gears can be accumulated in this manner before filler pass welding is done. I. FILLER PASS WELDING a. The accumulated root run welded gears are placed side by side on a holding table, which is either flat or slightly tilted up to permit down hand welding of the filler pass. b. Use MIG welding with the same wire as used in the root run. 100% CO2 shielding gas is used in the fill pass. The wire feed is 2300mm- 3540mm (90-100 inches) per minute, at 250-280 Amp and 26-32 Volts. c. Weld one side of each of the accumulated gears. d. Turn each of the gears 90 degree and weld the second side of each gear. Continue this process till all 4 sides have been welded. The WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 27 of 38 fill pass should leave a weld bead that protrudes just above the housing surface. e. All welds are to be ground flush. The finished gear assemblies are then box gauged with Gage 27200 for dimensional acceptability. J. PRE-SHORTENING & PAINTING The assembled RF-361 draft gear must be pre-shortened to facilitate installation into the yoke and draft pocket. a. Place the gear under a 200 ton open gap press, position the pre-shortening block (Drg. no 25658) on the shoes and apply a load. Compress the gear until there is sufficient vertical clearance between the housing and wedge lugs to insert standard powdered metal. Attach tap to 3 inserts (cube) using taps lower inserts through openings. b. Check the pre shortened length (using gauge 27207) c. After pre-shortening the external surfaces of the draft gear is to be painted with black or blue paint. 810. MAINTENANCE OF MARK-50 DRAFT GEAR Note: - All the drawing no., part no. and gauge no. mentioned hereunder are as per literature of M/s BESCO. A. INSPECTION a. The draft gear shall be inspected whenever wagons are coming in ROH depot. The following instructions shall be followed to determine whether draft gear is in normal released condition or in stuck condition. b. A normally released draft gear would appear as shown in Fig 8.6, where the follower plate is against the front lugs, the housing is against the rear lugs and the components of the friction clutch are fully returned to their neutral position. The internal spring forces in a normal fully released Mark 50 draft gear will be from 7,000 kg to 10,000 kg. c. It is possible for a slight gap to be seen at either the front or rear draft lugs when the draft gear is in a normal fully released position, e.g. in an enlarged draft gear pocket. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 28 of 38 B. REMOVAL OF DRAFT GEAR FROM WAGON POCKET When a draft gear with follower plate is installed into the pocket of a wagon, it has ample initial spring load to provide a tight fit into the draft gear pocket. While removing the draft gear from the wagon pocket, it is necessary to compress the draft gear approximately 6.35 mm (1/4”). In order to clear the front and rear stops, a suitable device can be used to compress the draft gear so that the draft gear and Yoke assembly may be free to be lowered from the wagon. a. NORMAL CONDITION I. Remove yoke pin support. Drop yoke pin down and draw coupler out of wagon. II. Place suitable lifting/lowering jack under yoke support plate. Holding yoke support in position with centre-sill, cut and take out rivets. III. Insert nut (Ref: RDSO manual G-80) in the yoke pin hole. Apply screw from the mouth and compress by rotating screw WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 29 of 38 by means of wrench so that the draft gear with follower is clear of the pocket length by about 6 to 8 mm. IV. Lower support at yoke support plate and take out yoke with draft gear and screw. V. Unscrew and remove nut. Now draft gear, follower is loose in yoke and they can be taken out separately. b. FOLLOWER BROKEN A broken follower will remain within pocket only if it is cracked at centre and split in two at centre vertically or horizontally. When cracked and split jerk by hammer or by pulling yoke forward to loosen the follower in the pocket. c. PARTIALLY STUCK GEAR In a partially stuck draft gear, the draft gear is loose in the pocket and the draft gear travel will be less than 82.55 mm (3-1/4”). d. FULLY STUCK DRAFT GEAR A fully stuck draft gear is one where the components of the friction clutch are jammed and flush with the open end of the housing. A large gap would appear at the front or rear stops or at both stops. The internal spring forces between 11,000 kg and 23,000 kg would propel the friction parts outward if the gear was to suddenly release. e. REMOVAL OF STUCK OR DAMAGED DRAFT GEAR WARNING: WEAR SAFETY EQUIPMENT INCLUDING HARD HAT, SAFETYGLASSES, SAFETY SHOES, GLOVES AND BODY PROTECTION I. When follower is not missing. DO NOT STAND OR WORK DIRECTLY IN FRONT OF COUPLER i. First move another wagon against the couple, forcing follower and draft gear against rear stops. Do not remove the yoke support plate. Securely weld draft gear housing and follower. ii. Cut gear housing in spring area to expose coil springs and cut each coil of every spring to eliminate the compressive force or the springs. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 30 of 38 II. Where yoke is broken and follower is missing i. First move another wagon against coupler forcing draft towards the stops as for as possible. ii. Remove a section of the yoke straps with the torch to permit installation of a follower and bracket IMPORTANT: The follower with the bracket must be installed with a lift table or fork truck to eliminate any one putting their hands near the open end of this stuck draft gear. Once fitted into place, i. Securely weld the bracket to the draft gear housing. ii. Remove coupler. iii. Position lift table or other lowering means under the support plate, yoke and draft gear. iv. Remove rivets from yoke support plate. Slowly lower down the assembly unit on the ground. v. Scrap draft gear, yoke and follower. C. REMOVAL OF STUCK DRAFT GEAR SO AS TO REUSE In case it is desired not to gas cut and scrap stuck draft gear as above, the following procedure may be adopted:- a. Place the stuck draft gear in front of a wall or 50 to 75 mm facing another working draft gear with follower. Force compressed air to clean any dust or mud from draft gear. b. Give sledge hammer blows with 8-10 kg hammer on the top front, side fronts, edges and rear wall. The inside components will be forced out. Re- examine this draft gear for any broken or unserviceable part. Re-use or reclaim the draft gear for use. D. INSPECTION OF MARK-50 DRAFT GEAR FOR RECONDITIONING Mark-50 draft gears have a built in wear life gauge. This is known as "plate clearance" and can be observed by looking up at the gear while it is in the wagon When the draft gear is out of the wagon a straight edge can be placed on the centre wedge of draft gear. Both movable plates should be driven or forced down until solid before measurement is made. The plate clearance is an indicator of the total surface wear of the friction components. When the plate clearance reduces to zero, the draft gear loses its effectiveness to cushion. Once the draft gear reaches this stage, some of the parts will start wearing on the housing and cause considerable damage, rendering it impossible to recondition. Cardwell recommended that Mark-50 draft gear should be inspected whenever wagon is in shop or under repair or when the draft gears are removed from the wagon. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 31 of 38 E. SUMMARIZED GUIDE TO DISMANTLE MARK-50 DRAFT GEAR  A press of 40 tonnes is required.  Press down with fixture D and insert the two pins.  Remove movable plate one side.  Remove wedge shoe same side.  Remove movable plate other side.  Remove wedge, shoe other side.  Turn and remove centre wedge.  Remove release spring.  Remove both tapered stationary plates.  Remove both outer stationary plates.  Apply fixture C and press to remove pins.  Remove spring seat.  Remove all coil springs and corner spring seats.  Reverse procedure for assembly. F. List of Gauges For Mk-50 Draft Gear a. Housing Gauges For Initial Inspection I. Housing reconditioned gauge No. BE-91/62-2 (No-Go Gauge to check minimum length of housing) II. Housing reconditioned Gauge No. BE-91/62-1 (GO Gauge to check maximum housing for Yoke and Sill clearance). III. Housing reconditioned Gauge No. BE-92/62-6 (No GO Gauge to check minimum housing wall thickness) IV. Housing reconditioned bottom flatness check b. Housing Weld Repair Gauges I. Reconditioned gauge No. BE-91/62-5 (No-Go Gauge to check to centre wedge stop area) II. Reconditioned gauge No. BE-91/62-3 (Go, No-Go Gauge to check movable plate area) III. Reconditioned gauge No. BE-91/62-4 & 5 (Go, No-Go Gauge to check on the wedge area) IV. Centre wedge gauging gauge No. BE-91/61-1 V. Spring seat gauging gauge No. BE-91/61-5 VI. Gauging centre wedge and spring seat for sorting gauge No. BE- 91/72-1. VII. Tapered stationary plate gauge No. BE-91/61-4 VIII. Outer stationary plate gauge No. BE-91/61-3 IX. Wedge shoe gauge No.BE-91/61-2. X. Gauging springs inner coil, corner coil & release gauge No. BE-91/61- 7&8 XI. Outer coil gauge No. BE-91/61-6 XII. Corner spring seat reclamation. XIII. Movable plate gauging gauge No. BE-91/61-10 Note: There are two maintenance publications i.e. G-76 for lines staff and G-80 for workshop staff issued by RDSO on “Inspection and Maintenance of Centre Buffer Couplers BG stock”. For Alliance-II CBC, RDSO has issued G-62 for inspection and maintenance by Train Examining and Workshop staff. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 32 of 38 811. Action plan to reduce Train Partings: A report on analysis of train parting was circulated by Railway Board vide letter No. 2012/m(n)/951/35 dated 14.09.2012 to Zonal Railways. This report highlighted that approx. 62% cases of train parting were due to uncoupling and approx. 38% due to breakages of components. The uncoupling cases were mainly due to lock defective/broken, lock lifting arrangement defective, knuckle worn out/defective and operating handle/bearing bracket defective. The components breaking were knuckle, CBC body/Shank and Yoke. This Report had the following recommendations – 1. Zonal Railways should strictly check and enhance replacement of knuckles, knuckle pivot pin, lock , lock lifter with toggle, yoke pin, operating handle and bearing piece during POH, ROH, Sick line and Yard maintenance. 2. DPT Test of knuckles during ROH. 3. Improve maintenance standard of CBC and Draft gear components. Vide Railway Board’s letter No. 2003/M(N)/951/22 dated 16.01.2013, List of must change items have been recommended during POH and ROH. A. During POH: Knuckle, CBC lock, Rotary lock lift assembly, bearing piece , yoke pin support plate liner and shank wear plate etc. B. During POH & ROH: Striker casting wear plate 4. Railway should send Report of every train parting to RDSO as per RDSO Proforma (Ref : RDSO letters Nos. MW/CPL/VG/D dated 11.05.2010 & 05.04.2013). 5. RDSO should also put up their analysis for train partings on Rail net every month (similar to hot axles) for a feed back to work shops, ROH depots and examination points. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 33 of 38 VENDOR LIST (As on 01.01.2013) (CENTRE BUFFER COUPLER) 1. HIGH TENSILE CBC COUPLER & ITS COMPONENTS FOR FREIGHT STOCK (SPEC-48-BD-08) 1. BESCO Ltd. 7B & C Poonam, 5/2 Russel Street, Calcutta-700001 2. Bhilai Engg. Corp. Ltd. Post Box No. 31, Industrial Area, Hathkhoj Village, Bhilai-490001 3. Braithwaite & Co.Ltd. Angus works, P.O. Angus Distt-Hoogly-712221 4. Burn Standard Co. Ltd. Nityadhan Mukharjee Road, Howrah-711101 5. Hindustan Engg. & Industries Ltd.. 27, Sir R.N. Mukharjee Road, Calcutta-700002 6. Raneka Industries Ltd. Plot No. 17, Sector III, Sagore, Pithanm pur, Distt. Dhar M.P. 7. Texmaco Rail and Engineering Ltd.(Steel foundary) Belgharia , 24 Paragana, Calcutta-700 056 8. Titagarh Wagon Ltd. (Unit: Titagarh steel) 113, Park Street, Calcutta-700 016. 9. Jupiter alloys & Steel (India)Ltd. 10. Fronteir alloy & Steel Ltd., 11. Titagarh Wagon Ltd. Heavy Engineering Division (TWL) 12. Siena Engg. PVT. Ltd. 13. Rine Engg. Pvt. Ltd. 14. Chittaranjan Locomotive Works, steel foundary, Chittaranjan 15. Rausheena Udhog Limited, Engineering Division 2. HIGH TENSILE CBC COUPLER & ITS COMPONENTS FOR LOCOMOTIVE (SPEC-56-BD-07) with amend No.1 of 10 & drawing no. SKDL-3430 1. BESCO Ltd. 7B &C Poonam, 5/2 Russel Street, Calcutta-700001 2. Chittaranjan Locomotive Works, steel foundary, Chittaranjan 3. Hindustan Engg. & Industries Ltd. 27, Sir R.N. Mukharjee Road, Calcutta-700002 4. Orient Steel Industries Ltd. 2, Brabourne Road, Calcutta-700001 5. Raneka Industries Ltd. Plot No. 17, Sector III, Sagore, Pithanm pur, Distt. Dhar M.P. 6. Texmaco Rail and Engineering Ltd.(Steel foundary) Belgharia , 24 Paragana, Calcutta-700 056 7. Titagarh Wagon Ltd. 113, Park Street, Calcutta-700 016. 8. Jupiter alloys & Steel (India) Ltd. 9. Frontier alloys & Steel Ltd. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 34 of 38 10.Titagarh Wagon Ltd. (Heavy Engg.) 11. Siena Engg. Pvt. Ltd. Plot No. 5-3/3 & 22, Sector (iii), Pithampur, Distt. Dhar. M.P. 3. ALLIANCE II COUPLER & ITS COMPONENTS (SPEC-24-BD-79) 1. BESCO Ltd. 7B &C Poonam, 5/2 Russel Street, Calcutta-700001 2. Raneka Industries Ltd. Plot No. 17, Sector III, Sagore, Pithanm pur, Distt. Dhar M.P. 3. Titagarh wagon Ltd.(unit titagarh steel) 113, Park Street, Calcutta-700 016. 4. Siena Engg. Pvt. Plot No. 5-3/3 & 22, Sector (iii), Pithampur, Distt. Dhar. M.P. 4. HIGH CAPACITY DRAFT GEAR (SPEC-49-BD-08) & drawing no. WD-81010-S- 03(Alt-9) 1. BESCO Ltd. MK 50 7B &C Poonam, 5/2 Russel Street, Cardwell design Calcutta-700001 2. Burn Standard Co. Ltd. RF-361 Nityadhan Mukharjee Road, Miner design Howrah-711101 3. Hindustan Engg. & Industries Ltd.. RF-361 27, Sir R.N. Mukharjee Road, Miner design Calcutta-700002 4. Titagarh Wagon Ltd. RF-361 113, Park Street, Calcutta-700 016. Miner design 5. Texmaco Rail and Engineering ltd RF-361 steel foundary kolkata. Miner design 6. Braithwaite RF-361 & Co. Miner design 7. Frontier alloys RF-361 Steel Ltd. Miner design 8. Jupiter alloys & steel (India Ltd) 9. Raneka Steel Ltd. 10. Bhilai Engg. Company Ltd. 5. TOP LOCK LIFT HOLE CAP (SPEC 48-BD-08) 1. Annpurna Engg. Works, 89/1, Deshprn, Sasmai Road, Howrah-711 101 2. Comet Technocom (P) Ltd. 37, Bhagwan Ganguly Lane, 3rd floor, Howrah-1 3. Decon India, 9 Duffer Street, Liluah, Howrah-4 4. Krishna Engg. Works, 57/9, Q Road, Netajigarh, (Belgachia) Howrah 5. Shiv Engg. Woprks, 64/4, G.T. Road, Liluah, Howrah 6. AD. Electro Steel Co-Pvt Ltd. Balti kuri (Surki mill) Howrah WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 35 of 38 7. Him Teknoforge Ltd. Village-Bhillanwali, Industries Area, Baddi (H.P.) 8. Devvrat Industries Co. Jalan Complex, Junglepur NH-6 Mouza Baniara, P.O. Donjur, Howrah, 6. KNUCKLE PIN WITH WASHER (SPEC 48-BD-08) 1. Anand Sales Corporation 6 Poonam chand Bagaria Belly, Howrah-711005 2. Annpurna Engg. Works, 89/1, Deshprn, Sasmai Road, Howrah-711 101 3. Comet Technocom (P) Ltd. 37, Bhagwan Ganguly Lane, 3rd floor, Howrah-1 4. Cosmic Engineers, 2, Duffer Road, Liluah, Howrah-711202 5 Krishna Engg. Works, 57/9, Q Road, Netajigarh, (Belgachia) Howrah 6 Lal Baba Industrial Corporation 78, Lalababu Shir Road, Belur, Howrah- 711 202 7 Melbro Engineering Works Pvt.Ltd., 1/1, “X” Road, Belgachia, Howrah 8 NF Forging Pvt Ltd. 72, Lalababu Shire Road, Belur, Howrah 711202 9. Royal Industries, 8, Kali Mazumdar Road, Ghusuri, Howrah 711107 10. Aglow Engg. Howrah-Amta Road Salap, Howrah 911409. 11. S.K. Industries, Ichapur,P.o.Santragachi, Howrah-4 12. Shree Engineers Ichapur H.I.T. Road, Santragachi Hawrah-4 13. AD. Electro Steel Co.Pvt. Ltd. Balti kuri (Surkimill) Howrah 14. Devvrat Industries Co. Jalan Complexm, Junglepur, NH-6 Mouza: Baniara, P.o-Donjur Howrah-711411. 8. YOKE PIN (SPEC 48-BD-08) 1. Anand Sales Corporation 6 Poonamchand Bagaria Belly, Howrah-711005 2. Annpurna Engg. Works, 89/1, Deshprn, Sasmai Road, Howrah-711 101 3. Comet Technocom (P) Ltd. 37, Bhagwan Ganguly Lane, 3rd floor, Howrah-1 4. Cosmic Engineers, 2, Duffer Road, Liluah, Howrah-711202 5. Krishna Engg. Works, 57/9, Q Road, Netajigarh, (Belgachia) Howrah WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 36 of 38 6. Lal Baba Industrial Corporation 78, Lalababu Shir Road, Belur, Howrah- 711 202 7. Melbro Engineering Works Pvt.Ltd., 1/1, “X” Road, Belgachia, Howrah 8. N.F. Forging Pvt. Ltd., 72, Lalbabu Shiv Road, Brlur, Howrah- 711 202 9. India Tools Craft Pvt Ltd.Hawrah Industries Estate, dhed No.34835 (L type) Dasnagar Howrah. 10. Devvrat Industries Co. Jalan Complex, Junglepur-NH6, Mouza= Baniara, P.o. Donjur Howrah. 11. AD Electro steel Co. Pvt. Ltd. 12. Aglow Engg. Howrah-Amta Road Salap, Howrah 911409. 13. Royal Industries, 8, Kali Mazumdar Road, Ghusuri, Howrah 711107 9. KNUCKLE THROWER (SPEC 48-BD-08) 1. Annpurna Engg. Works, 89/1, Deshprn, Sasmai Road, Howrah-711 101 2. Krishna Engg. Works, 57/9, Q Road, Netajigarh, (Belgachia) Howrah 3. Lal Baba Industrial Corporation 78, Lalababu Shir Road, Belur, Howrah- 711 202 4. AD. Electro Steel Co-Pvt Ltd. Balti kuri (Surki mill) Howrah 5. Him Technoforge 6. East India Steel Pvt.Ltd. Industrial Aria, Roulkela-769004. Note: the above vendor list is only indicative and updated by RDSO after every Six Months. The current status of the vendors may be taken from vendor directory available on the RDSO website. WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 37 of 38 MARKING ON CBC (MANUFACTURERS INITIAL) WAGON MAINTENANCE MANUAL CHAPTER 8-DRAW AND BUFFING GEAR Page 38 of 38 FIG. 8.14: MARKING OF PARTS WAGON MAINTENANCE MANUAL