The length of side buffer for CBC-equipped SLR (FV & LV) is maintained to 635 mm as per RDSO drawing no. SK - 98145 (Ref: Carrg. Dte/RDSO letter no. MC/BLB/CBC dtd 17.02.08).

The projection of buffer from the head should be within 600 mm to 635 mm as per maintenance requirements for side buffer assemblies.

When telltale slot is not clear and rotary lock lift lever rib is not vertical, it indicates partial locking of knuckle. This is dangerous as it gives false indication of coupler locking, and the coupler may open during run.

The yellow marking should be on or about toggle pin of rotary lock lifter assembly such that it is not worn due to coupling-uncoupling operation and is completely visible when lock lift lever is fully dropped, and not visible in case of half locking.

RDSO issued a marking scheme of painting lock lift lever with bright yellow paint of approx. 2" diameter (round) on or about toggle pin of rotary lock lifter assembly to improve visibility, especially in inadequate light.

Determine distance to lower by subtracting required height from actual, loosen carrier bolts, pry carrier up, remove tack weld to remove shims, tack weld remaining shims, retighten bolts, lower jack, and inspect final height.

After inserting shim(s) between coupler carrier and striker support from the front, tack weld the shim or shims to the striker support to secure them in position before retightening coupler bolts.

The original thickness of coupler wear plate is 1/4 inch. If wear plate is reduced to 1/16 inch, it shall be replaced during height adjustment or maintenance.

To restore to level position, add shims on the coupler carrier. Excessive shimming should be avoided to maintain necessary vertical height of the coupler. When couplers are level, no shimming should be done at the carrier.

To check levelness, suspend a weighted string against the machined front face of the knuckle when the coach is on a level track. Measure the distance from front face to string - maximum should be not more than 1/4 inch.

The phonic wheel bolt M8x35 must be tightened to 30 Nm torque as per RDSO letter no MC/CTRB/Genl dated 10.08.2021.

The security disc screw M20x60 must be tightened to 200 Nm torque using a calibrated torque wrench, ensuring secure mounting of the security disc.

As per RDSO L/No. MC/CTRB/Defects dt-29/12/17, the pressing force for TIMKEN make CTRBs is 17-29T, revising the earlier specification of 37-42 tonnes.

Original diameter of knuckle pivot pin is 1-5/8 inches. If worn more than 25%, replace pivot pin and cotter pin by comparing pin thickness to thinnest part of wear.

All M16 nuts and bolts of front and rear carrier plates must be tightened diagonally to 180-200 N-m torque to ensure secure mounting of the draft gear assembly.

The specific sequence: rear carrier plate & BDG on trolley, raise, tighten wedge lock loosely, align holes, bolt rear carrier plate diagonally (180-200 N-m), fit supporting device (500-550 N-m), fit coupler head with main pin, then fit front carrier plate.

The AAR type H coupler has maximum vertical gathering range of ±90 mm and horizontal gathering range of ±110 mm, enabling automatic coupling even when vehicles are vertically misaligned within this range.

As per maintenance note, only dry lubrication as per Para 3.2 and 7.3 of RP-004-98 Rev. 02 or latest should be done in schedule III to prevent unintended sliding of internal parts.

As per Para 7.2 of APTA RP-M-004-98 Rev.02 or latest, no painting should be done on any part or the assembly after overhaul except where specifically advised by RDSO, ensuring proper fit and function.

The supporting device bolts (M20x50 mm) must be tightened to 510 Nm torque value, and use of thread locking agent is recommended to prevent loosening under dynamic loads.

When inserting new support pin, inspect to ensure cotter pin hole is visible beyond the back edge of the knuckle pin lug on the coupler body before releasing knuckle pin and inserting new cotter pin.

If actual measurement is desired, inscribe a line on top of the toggle along the rear face of the knuckle tail shelf. Measure at point "C" - the measurement must not be less than 3/8 inch.

During anti-creep inspection, if the front edge of the toggle is 1/8 inch or more forward of the rear corner of the knuckle tail shelf, the anti-creep is unacceptable and the lock lift assembly must be replaced.

The correct sequence requires supporting knuckle weight, removing cotter pin and support pin, pushing up knuckle pin, removing cotter pin, lowering knuckle pin, inserting new pivot pin from bottom, inserting cotter pin, then installing new support pin and cotter pin with careful attention to safety.

After supporting coupler head with jack and raising to proper height, the gap between the top of coupler carrier and bottom of coupler shank wear plate must be measured to select a combination of shims that most closely equal the gap measurement.

The reference coupler height center of coupler to rail is 1105 mm (43.5 inches). During height adjustment, coupler height should be 34 to 35 inches with 34-1/2 inches preferred, requiring careful shim selection.

Vertical height aligning wing pocket and guard arm gauge No. 34101-4 (APTA gauge) is a GO gauge that must pass (slide into) the wing pocket and over the guard arm. If it does not pass, there is vertical distortion.

Vertical height condemning limit aligning wing pocket and guard arm gauge No. 44250-5 (APTA gauge) is a NO-GO gauge that must NOT pass into the wing pocket or over the guard arm, indicating excessive wear if it passes.

Aligning wing limit gauge No. 32600 (APTA gauge) is used to inspect for excessive distortion of the guard arm of the coupler head. The gauge must seat against front face and pivot lug and clear at all points.

Knuckle nose wear and stretch limit gauge No. 34100-2A (APTA gauge) verifies that points A, B, and C seat on the knuckle and that point D does not touch or clear more than 1/4 inch.

Contour condemning limit gauge No. 34100-1 (APTA gauge) is used to inspect limit of contour slack, which has been set at 3/8 inch. The gauge must not pass between the front face of coupler head and pulling face of knuckle.

Step I: Insert pry bar through front of coupler between knuckle tail shelf and lock, forcing lock upward. Step II: Insert pry bar between leg of lock and front of lock hole, pull toward front of coupler to force lock leg rearward to check anti-creep.

In lateral damper, fit such that "THIS SIDE DOWN" sticker faces the ground. The side with protection cover must be kept at the upper (elevated) side to be mounted on bolster, ensuring proper function and longevity.

The correct size of nylon nut is M16 X 1.5 (1.5 mm pitch size). Using standard M16x2 nut damages the damper end spindle threads, requiring careful attention during maintenance.

To extract the central/main pin, an M16 bolt duly welded on a T-shaped rod should be inserted in the central pin and tightened slightly, then pulled carefully. If difficulty is felt, shake the coupler head.

The correct sequence is: unscrew M16 bolt of support bracket outer, pull rotary bar handle, remove uncoupling hook, hang/secure coupler, remove supporting device, remove stiffener plate, then extract central pin using M16 bolt welded on T-shaped rod.

The wedge lock must be tightened in a zig-zag manner up to 400-450 N-m torque during mounting of the draft gear to ensure even compression and proper seating.

As per RDSO/2011/CG-03 (Rev.03), the draft gear shall be suitably pre-compressed with preload of 10 kN - 20 kN, ensuring proper initial compression of the elastomeric pads.

As per the technical data, draft gear dynamic capacity is 35 kJ minimum for RDSO/2011/CG-03 (Rev.01) and 20 kJ minimum & not exceeding 35 kJ for Rev.03, showing a specification change.

In integral shank type couplers, articulation is through the main pin connecting draft gear and coupler head. In muff coupling type (Dellner/Faiveley), the coupler head and draft gear are joined through muff coupling with articulation of coupler head through elastomeric pads, providing better riding behavior.