Double Decker coach maximum BC pressure shall be from 3.8 kg/cm², and the BC filling time shall be recorded from 0 to 3.6 kg/cm² during testing.

The clearance between brake disc and brake pad should be 1.5 mm for proper operation, ensuring smooth running while maintaining effective braking when required.

During Passenger Emergency Pull Box testing, the BP pressure should remain 2.0 ± 0.2 kg/cm², the brake accelerator should respond, and BP pressure should exhaust from emergency Brake valve.

The anti-skid device gets power supply at 1.8 ± 0.2 kg/cm² and power supply turns off at 1.3 ± 0.2 kg/cm². This ensures the WSP system activates only when sufficient pressure is available.

The BC release time from maximum pressure to 0.4 kg/cm² should be 15-20 seconds during release of emergency brake application.

During emergency application, the charging time of brake cylinder from 0 to 3.6 kg/cm² should be 3-5 seconds, and the brake accelerator should respond with a blast of air.

In full brake application, the maximum BC pressure should be 3.0 ± 0.1 kg/cm², with leakage in BC pressure within 5 minutes being less than 0.1 kg/cm².

For full brake application test, the BP pressure should be reduced from 5.0 to 3.4 kg/cm² in 3-5 seconds, during which the Brake Accelerator should not respond.

In the sealing test, after allowing the system to settle for 2 minutes after charging, the rate of leakage should be less than 0.02 kg/cm²/minute for both BP and FP.

The charging time of CR (0-4.8 kg/cm²) is 60-120 seconds for SAB/FT make and 160-210 seconds for KB make, as per the testing specifications.

According to the single car testing specifications, the charging time of AR (0-4.8 kg/cm²) is 175±30 seconds for SAB/FT make and 165±20 seconds for KB make.

M8 size screw to IS 1367 pt.iii Class 10.9 along with spring washer to IS 3063 type-B should be used for securing phonic wheel. LOCTITE 243 or equivalent glue should be used to ensure rigid connection.

The Phonic Wheel screws should be tightened with 30 N-m torque to ensure secure fitment. M8 size screws to IS 1367 pt.iii Class 10.9 along with spring washer to IS 3063 type-B should be used.

The clearance between the phonic wheel and speed sensor should be 0.9 to 1.4 mm in case of KB make, FTIL make & Escorts make WSP. This gap should be checked in D3 schedule or whenever required.

During WSP testing, checking the WSP processor for correct reading '99' on the electrical panel inside the coach indicates that the WSP system is functioning normally and is OK.

The SWKP AS 20R WSP system measures and evaluates axle speed separately within a speed range of 2 to 400 km/h, making it suitable for high-speed train operations.

The brake discs have a groove around their circumference to show when they reach their condemning limit and have to be replaced. When friction ring wear reaches 5 to 7 mm marked by the groove, replacement is necessary.

The brake discs are ring-shaped castings with crosswise cooling ribs that carry off the heat generated during braking and serve simultaneously to maintain a thermal balance within the friction rings.

In the type designation W 640 B 110 P G U P, W stands for Axle-mounted brake disc, 640 is the diameter of friction ring, B means Ventilated, 110 is width of friction ring, P is Flange seat, G is Gray cast Iron, U is Unsplit, and P is Pneumatic.

Worn brake linings must be replaced at a residual thickness of 5 mm at the latest, and at no point must the residual pad thickness fall below 7 mm for safe operation.

The maximum amount of wear allowed between the pins and bushings is 1 mm (0.5 mm each side). When this limit is exceeded, the bushings and pins must be replaced.

Each axle is equipped with two brake discs, ensuring that brake energy is dissipated only at the brake discs while wheel sets are stressed only by the weight of the coach, avoiding superposition of thermal and mechanical stresses.

Emergency brake valves must be installed upright with exhaust port O pointing downwards to ensure proper operation and drainage of any condensate.

The emergency brake valves restrict the residual pressure in the brake pipe L to about 2 bars due to the elevated force of compression springs, shortening the time needed to refill the brake pipe substantially.

The Emergency Brake Pull-box has a maximum acceptable working pressure of 10 bar and maximum voltage across switch of 110 VDC.

Two types of flexible hoses are used: Flexible Hose - 650 mm for bogie (Drawing no. CG-19036) and Flexible Hose - 500 mm for Brake actuators (Drawing no. CG-19037), complying with RDSO L/No. MC/LHB/Brake dated 23.08.2019.

A leaf spring on the stem presses the operating handle downwards, seating the handle in deep grooves at ON/OFF positions, resulting in a mechanical lock that prevents accidental movement.

The cut off angle cock consists of cap and body holding a steel ball inside which is seated on nitrile rubber seats, providing effective sealing and long service life.

The ball in the cut off angle cock has a special profile with a groove at the bottom portion for venting air to atmosphere when the cock is in closed position. This ensures safe uncoupling of hoses.

The indicator plate fastened to the piston rod is subdivided into two color fields (green and red). With pressure below 0.6 bar, the piston is in lower position showing green; with pressure above 0.6 bar, the piston rises showing red through the Plexiglas window.

The filter has an orifice cross-section of approximately 280 mm² (Φ19 mm) with a connecting diameter of 18.19 mm, allowing adequate air flow while maintaining filtration efficiency.

The filter insert withholds particles larger than approximately 0.1 mm, protecting downstream devices from contamination, malfunction, and damage. The filter mesh is precisely 0.1 mm.

Air receivers should be hydraulically tested at test pressure of 16 kg/cm² during shop schedules (POH) to ensure safety and structural integrity of the pressure vessels.

Two types of stopcocks are available: 2/2-way valves and 3/2-way valves. These manually operated units serve to charge, shut off, and vent compressed air systems in rail vehicles.

After full braking, Brake Pipe pressure can be increased to 6 bar for faster brake release, with a protective feature preventing overcharge of Control Reservoirs from 5.0 kg/cm² to 6 bar for a minimum of 25 seconds.

The brake does not apply when Brake Pipe pressure drop is less than 0.3 bar in 60 seconds. This insensitivity feature prevents unintended brake applications due to minor pressure fluctuations.

The brake applies within 1.2 seconds when Brake Pipe pressure drops by 0.6 bar in 6 seconds, as per UIC No. 547 specifications. This ensures quick and responsive braking action.

With Brake Pipe regime pressure at 5.0 kg/cm², the Distributor Valve restricts Brake Cylinder pressure to 3.8 ± 0.1 bar maximum, even in full service or emergency application. This pressure limiting feature prevents over-braking and wheel damage.

When brakes are applied, the minimum pressure limiter causes the brake cylinder to charge quickly to about 10% of the brake force reached in a full service brake application. This initial pressure increase, called the "response," overcomes friction in the brake rigging quickly and brings the brake shoes into position with certain force.

At the start of braking, air from the brake pipe flows into the quick-service chamber, causing volume expansion that propagates the braking pulse quickly through the train, achieving a propagation rate of 285 m/s. This ensures rapid brake application throughout the train length.