During leakage test of the supporting device's air springs (where applicable), after 15 minutes at internal pressure, pressure drop should not be more than 1% of Test Pressure.

Before uncoupling, it is common practice to push the vehicles together (with one vehicle applied with parking brake) to avoid excessive binding in the system and make uncoupling easier.

After coupling, the tertiary locking pin arrangement must be locked by inserting the locking pin in its groove to ensure the coupler remains securely locked and cannot accidentally uncouple.

The coupler should be checked for proper locking under normal operating conditions, ensuring the lock lift lever is completely dropped and locking is secure.

The coupler shank wear plate should be checked for wear. If worn more than 3/16 inch (3-4 mm), the coupler wear plate should be replaced to maintain proper fit.

Mounting brackets (2 types) are mounted on the vehicle structure, and the manual uncoupling device is fastened to these mounting brackets, providing proper positioning.

Only dry lubrication should be done in schedule III as per Para 3.2 and 7.3 of APTA-RP-M-004-98 Rev. 02 or latest, preventing lock sliding issues.

The knuckle and coupler head machined faces should be parallel when the knuckle is in closed condition, which can be examined visually during inspection.

As per RDSO marking scheme, the lock lift lever is marked with bright yellow paint (approximately 2" diameter round) to improve visibility, especially in inadequate light.

No oil or grease should be applied on coupler internal parts such as Knuckle, Lock, Rotary Lock Lifter etc., as this can cause the lock to slide and lead to automatic uncoupling.

The locking plate bolts (M16) are to be tightened to 200 Nm torque and locked with spring dowel/split pin for security.

The coupler height (center of coupler to rail) should be maintained at 1105 mm (approximately 43.5 inches) for proper mating with other vehicles.

The coupler assembly should be completely dismounted from coach and overhauled during Shop Schedule-III, which occurs every 6 years.

The wedge lock must be tightened in a zig-zag manner up to 400-450 Nm torque when mounting the draft gear, ensuring proper preload.

The M16 nuts and bolts for mounting plates must be tightened diagonally to 180-200 Nm torque, ensuring even clamping force.

Grease should be applied on the wear plate of the supporting device to reduce friction and wear between the coupler head and the supporting device.

The supporting device is fastened using four bolts M20x50 mm tightened to 510 Nm torque value, ensuring secure mounting.

The supporting device comprises four preloaded compression springs that support the coupler weight and allow vertical movement during operation.

The supporting device comprises four preloaded compression springs and supports the coupler weight, with the coupler head resting on its top wear plate, allowing vertical movement.

It is very important to use only high tensile bolts (Grade 10.9) for fastening the mounting plates to ensure safety and strength under operating loads.

Uncoupling is only possible from the right side of the coach when looking at the end wall of the coach, providing consistent operation across the fleet.

After proper coupling, the telltale slot should be clear of the Rotary Lock Lift Lever, and the Rotary Lock Lifter rib should be vertical, providing visual confirmation of secure coupling.

At least five coaches of the rake should be braked first before pushing the vehicle for coupling, ensuring safe and controlled coupling operation.

Vehicles should be pushed slowly at approximately 2-3 km/h for coupling to ensure proper engagement without damage to coupler components.

The coupler system can negotiate curves with a minimum radius of 175 m, providing flexibility in train operations on sharp curves and yard tracks.

The maximum travel of draft gear in draft/tensile mode is 58 mm, absorbing energy during pulling forces and providing smooth train handling.

The maximum travel of draft gear in buff/compression mode is 90 mm, absorbing impact energy during buffing and protecting the vehicle structure.

The complete coupler assembly, including the head and draft gear, weighs approximately 600 kg, requiring careful handling and appropriate lifting equipment.

The coupler head weighs approximately 230 kg, making it a substantial component that requires proper handling equipment during maintenance and replacement.

The coupler length from pivot to coupling line is 1030 mm, which is a standard dimension for this type of coupler, ensuring proper geometry and force transmission.

The coupler has a tensile strength (yield) of 1000 kN, allowing it to withstand significant draft/tensile forces during train pulling operations.

The coupler has a compressive strength (yield) of 2000 kN, allowing it to withstand significant buffing forces during train operations and shunting.

The coupler head material conforms to AAR specification M 201 Grade 'E', which provides the required strength and durability for heavy-duty railway applications.

The connection between draft gear and coupler head is through the main pin, which allows articulation of the coupler head while transmitting forces between the components.

The coupler system uses Balanced Draft Gear (BDG) which comprises two separate elastomeric pads stacks - one for buff mode and one for tensile/draft mode, providing balanced energy absorption in both directions.

The Coupler System allows a horizontal angle of deflection of 10 to 18 degrees on either side of the coupler center line, allowing negotiation of curves and track irregularities.

The Coupler System allows a vertical angle of deflection of 4 to 7 degrees on either side of the coupler center line, accommodating track grade changes and vertical curves.

The coupler system has a maximum horizontal gathering range of ±110 mm, allowing automatic coupling even when there is lateral misalignment between vehicles.

The AAR type H coupler enables automatic coupling with maximum vertical gathering range of ±90 mm and horizontal gathering range of ±110 mm. This allows coupling even when there is vertical misalignment between vehicles.

The center buffer couplers used on AC LHB coaches are tight lock center buffer couplers of AAR type H. They can be coupled with AAR type "E" center buffer couplers fitted on locomotives.