Wagon Airbrake System,indian Railways.

AIRBRAKE SYSTEM INDIAN RAILWAYS Created by A.srinivas, junior engineer, Wagon workshop, rayanapadu,vijayawada.

SAFE WORKER IS THE BESTWORKER

TOPICS Introduction & Types Of Air Brake System Principal Operation Of Single & Twin Pipe System Advantages Of Twin Pipe System Types Of DV & Operations Of EKDV Modification Of The Air Brake System (LSD,EL-60) BMBS Working System & Advantages - Disadvantages SWTR & Rake Testing

AIR BRAKE SYSTEM

AIR BRAKE SYSTEM INTRODUCTION:-

 In the air brake system, a lot of developments have taken place such as bogie mounted Air brake system, Twin pipe air brake system, Automatic load sensing device etc,. As a result, the maintenance and requirements have changed considerably.

AIR BRAKE SYSTEM CLASSIFICATION OF AIR BRAKE SYSTEM:

On the basis of type of release, air brake system is classified as:

1. 2.

Direct release air brake system. Graduated release air brake system.



Both Direct and Graduated release are further available in two forms viz.

1. 2.

Single pipe and Twin pipe

On the basis of type of fitment, air brake system is classified as: 1.Under frame mounted air brake system. 2.Boige mounted air brake system.

AIR BRAKE SYSTEM  The graduated release air brake system consists of following components:1. 2. 3. 4. 5. 6. 7.

Distributor valve. Common pipe bracket with control reservoir. Auxiliary reservoir-100 Litres & 75 Litres. Brake cylinder 355mm dia. , 300 mm dia.,BMBS & BMBC. Isolating cock. Three way centrifugal dirt collector. Cut off angle cock (32mm size on either ends of brake pipe & feed pipe). 8. Air brake hose coupling (32mm for brake pipe / 32 mm from feed pipe). 9. Brake pipe/feed pipe (32mm dia). 10. Branch pipes from BP/FP to brake equipment (20mm bore). 11. Guard emergency brake valve. 12. Pressure gauges for BP/FP. 13. Quick Coupling.

AIR BRAKE SYSTEM  The processes involved in working of

graduated release air brake system are:-

1. CHARGING STAGE. 2. APPLICATION STAGE. 3. RELEASE STAGE.

CHARGING STAGE 5

kg/cm2

BC

charging time 3 - 4 min. 5kg/cm2

DC

Created BP by A.srinivas JE/AB/WWS/GTPL/SCR DV CPB

Driver brake valve

AR

5kg/cm2

C R

5kg/cm

2

Created by srinivas

During this stage, brake pipe is charged to 5kg/cm2 pressure which in turn charges control reservoir and auxiliary reservoir to 5 kg/cm2 pressure via distributor valve. At this stage, brake cylinder gets vented to atmosphere through

APPLICATION Application time 1.5 STAGE

5

2 DROP kg/cm

BC

18 - 30 sec.

5kg/cm2 2 3.5kg/cm

3.8kg/cm2

DC

Created BP by A.srinivas JE/AB/WWS/GTPL/SCR DV CPB

Driver brake valve

AR

45kg/cm kg/cm22

C R

5kg/cm2

Created by srinivas

For application of brakes, the pressure in brake pipe has to be dropped. This is done by venting air from driver's brake valve. Reduction in brake pipe pressure positions the distributor valve in such a way that the control reservoir gets disconnected from brake pipe and auxiliary reservoir gets connected to brake cylinder. This results in increase in air pressure in brake cylinder resulting in application of brakes. The magnitude of braking force is proportional to reduction in brake pipe pressure. NOTE:- 1. Brake Application takes places when Brake pipe pressure is

RELEASE STAGE

1.5 5

DROP2 kg/cm

BC

release time 45 - 60 sec. 5kg/cm2 2 3.5kg/cm

3.8kg/cm2

DC

Created BP by A.srinivas JE/AB/WWS/GTPL/SCR DV CPB

Driver brake valve

AR

4 5 kg/cm kg/cm22

EXHAUST

C R

5kg/cm

2

Created by srinivas

For releasing brakes, the brake pipe is again charged to 5kg/cm2 pressure by compressor through driver‟s brake valve. This action positions distributor valve in such a away that auxiliary reservoir gets isolated from brake cylinder and brake cylinder is vented to atmosphere

CHARGING

BC

NEED 2 6kg/cmFOR APPLICATION FP

DC

5kg/cm2

CreatedBPby A.srinivas JE/AB/WWS/GTPL/SCR DV CPB

NRV

AR

6kg/cm2

C R

5kg/cm

2

Created by srinivas

TWIN PIPE SYSTEM:In addition to the brake pipe, there is one more pipe called feed pipe Running from loco to the brake van to charge the auxiliary reservoir to 6kg/cm2.Up to 5kg/cm2 it is charged by both BP & FP. Beyond 5kg/cm2 & up to 6kg/cm2 it is exclusively

READY TO APPLICATION

CHARGING

BC 6kg/cm2

FP

DC

5kg/cm2

CreatedBPby A.srinivas JE/AB/WWS/GTPL/SCR DV CPB

NRV

AR

6kg/cm2

C R

5kg/cm

2

Created by srinivas

TWIN PIPE SYSTEM:In addition to the brake pipe, there is one more pipe called feed pipe Running from loco to the brake van to charge the auxiliary reservoir to 6kg/cm2.Up to 5kg/cm2 it is charged by both BP & FP. Beyond 5kg/cm2 & up to 6kg/cm2 it is exclusively

ADVANTAGES OF TWIN PIPE RDSO, which is the highest technical body on Indian Railways and functions as the Technical Advisor to the Railway Board had conveyed to them vide their letter No.MW/APB/TP/M dated 27.02.2003, as under Railway Board has also taken a decision to procure all freight wagons suitable for 100 kmph operation. It is proposed that all newly built wagons suitable for 100 kmph operation shall be fitted with twin pipe brake system. The advantages of providing twin pipe brake system are as under: (i) Provision of twin pipe will result into improved application and release of brakes. (ii) Due to improved release timings of twin pipe, it would be easier for driver to control the train. (iii) Due to improved release and application timings, drag on the train will be reduced resulting into better fuel economy/reduced drag would also mean reduced shuttling action and in turn reduced longitudinal forces on coupler and draft gear system.

ENROUTE BP FAILURE

BC

6kg/cm2 5kg/cm

FP

0kg/cm2 5kg/cm

CreatedBPby A.srinivas DV JE/AB/WWS/GTPL/SCR AR ISOLATING COAC

DC

CPB

CR

Created by srinivas

BYPASS TWIN PIPE SYSTEM:In case due to any reason brake pipe of a coach or any wagon gets damaged or goes defective, it can be bypassed in twin pipe system and the detachment of the coach or wagon would not be essential as in the case of single pipe

HEART OF DISTRIBUTOR THE VALVE AIRBRAKE

DISTRIBUTOR VALVE Distributor valve is the most important functional component of the air brake system and is also sometimes referred to as the heart of the air brake system.  The function of the distributor valve is to distribute compressed air received from brake pipe to auxiliary reservoir and control reservoir. In addition to this it also senses drop and rise in brake pipe pressure for brake application and release respectively. 

 It is connected to brake pipe through branch pipe. Various other components connected to the distributor valve are auxiliary reservoir, brake cylinders and control reservoir.  The distributor valve is removed for overhaul, maintenance & replace without disturbing the pipe

DISTRIBUTOR VALVE 

Two designs of distributor valves are in use on wagons. These are:

1) KE Type distributor valve. 2) C3W Type distributor valve.  The KE type distributor valve consists of the following main subassemblies:1. Three pressure valve 5.

KE DV / R-CHARGER ASSEMBLING In dv assembling R-CHARGER  48 no.s must change items,  64 no.s spare parts,  20 no.s bolts & nuts, total near about 140 items are used.  around 60 Tools are used in assembling.

FUNCTIONS The function of Rcharger are  To charge the auxiliary reservoir from BP to 5 kg/cm2 in single pipe system during charging.  It prevents back flow of air from AR to BP during brake application.  To isolate the DV in

KE DV / A-CONTROLLER ASSEMBLING

FUNCTIONS The functions of Acontroller are  It charges control reservoir

to 5 kg/cm2 from BP during charging.  It isolates the CR from BP,

when the brake pipe pressure is reduced at the faster rate, during sensitivity range.  It connects CR with

BP,when the brake pipe pressure is reduced at the slower rate, during

KE DV / U-CONTROLLER ASSEMBLING

FUNCTIONS  The function of U-

controller is to reduce the brake pipe pressure further by 0.4 kg/cm2, in addition to brake pipe pressure reduced by the driver from the loco, to accelerate the brake application. As soon as BC gets a pressure of 0.4 kg/cm2,The U-controller

KE DV / 3 PRESSURE VALVE ASSEMBLING

FUNCTIONS  It connects AR with BC

during brake application.  It connects BC with Exhaust during brake release.  It admits BC pressure in steps, when the brake pipe pressure is reduced in steps, to facilitate graduated application.  It releases air from BC

KE DV / MIN.PR.LIMITER ASSEMBLING

FUNCTIONS  The function of MIN.pressure

limiter is to admit a pressure of 0.8kg/cm2 immediately into the BC during brake application to overcome the resistance offered by the brake rigging.  It is a non restricted passage

between AR & BC.  Initially during brake

application the air from AR is sent into BC through two passeges.one with restrictions and another without restrictions. as soon as BC gets a pressure of 0.8 kg/cm2 the min.limiter closes

KE DV / MAX.PR.LIMITER ASSEMBLING

FUNCTIONS  The function of

MAX.pressure limiter is to admit a max.pressure of 3.8 kg/cm2 even emergency application.  It is a restricted passage

between AR & BC.  When the BC gets a

pressure of 3.8 kg/cm2 max. limiter closes the restricted passage. and this passage is closed, the AR completely disconnected from

KE DV / QUICK RELEASE VALVE

ASSEMBLING

FUNCTIONS  The function of quick

release valve is to release the air from CR manually to facilitate manual release.  NOTE:- In case of C3W

DV, it is a double release valve and it is to release the air from CR as well as from AR manually. 1. When the release valve

is pulled only

KE DV / CHOKE COVER

ASSEMBLING

FUNCTIONS  The choke cover has

application & release chokes inside it. The application and release chokes help in regulating the application and release times of brake.  The following are the

different hole sizes used in our workshop. 1. BOXN,BCN,BTPN,BOBYN,BC

NHL & etc. application/release choke hole size - 1.7/1.7 mm

3-PR.VALVE

0 kg/cm2 U-CTLR

EXH

A-CTLR

MAX.LR

B C

MIN.LR

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR

5 kg/cm2

EXH

R-CHARGER

5

kg/cm2 QRV

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

CR

5 kg/cm2

CHARGING

OFF Created by srinivas

ON

3-PR.VALVE

0 kg/cm2 U-CTLR

EXH

A-CTLR

MAX.LR

MIN.LR

B C

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR

5 kg/cm2

EXH

R-CHARGER

5

kg/cm2 QRV

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

CR

5 kg/cm2

CHARGING

Created by

ON

3-PR.VALVE

0.6 3.7 – 3.6 3.9 0 kg/cm kg/cm22 U-CTLR

0.4

EXH

A-CTLR

0.2

MAX.LR

MIN.LR

3.8 0.8

B C

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR

4.14 2 54.7-4.2 kg/cm kg/cm2

EXH

R-CHARGER

QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

5

kg/cm2

CR 4.8-3.7 3.6-3.4 0.2 - 1.6 1.3 51.4 kg/cm2 DROP

APPLICATION

Created by

3-PR.VALVE

TAKE LAP POSITION U-CTLR

EXH

3.7 kg/cm2 1.25– -3.9 3 0 kg/cm2

A-CTLR

MAX.LR

GRADUATED APPLICATION

MIN.LR

B C

GRADUATED RELEASE

AR

Decrease BP pressure

Increase BP pressure

BP {kg/cm2}

BC {kg/cm2}

BP {kg/cm2}

4.8 EXH

0.6

3.6

4.6

1.2

R-CHARGER 3.8

3.6

1.8

4.0

3.0

2.4

4.2

2.4

CR

3.0

4.4

1.8

3.8 3.6-3.4

3.6

4.6

1.2

4.8

0.6

Created by A.srinivas JE/AB/WWS/GTPL/SCR QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

4.4 4.2 4.0

5

kg/cm2

3.6 1.4 0.5 - 1.6 1.2 3.8 5 kg/cm2 DROP

APPLICATION

BC {kg/cm2} 4.14 54.7-4.2 kg/cm2 kg/cm2 kg/cm 3.8 2

Created by

3-PR.VALVE

3.7 – 3.9 0 kg/cm kg/cm22 U-CTLR

EXH

A-CTLR

MAX.LR

MIN.LR

B C

AR

Created by A.srinivas 0 JE/AB/WWS/GTPL/SCR

- 4.1 2 54kg/cm kg/cm2

EXH

R-CHARGER

QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

5

kg/cm2

CR 0

5

2 5 kg/cm DROP

EMERGENCY

Created by

3-PR.VALVE

3.7 – 3.9 0 kg/cm kg/cm22 U-CTLR

A-CTLR

MAX.LR

MIN.LR

EXH

B C

AR

Created by A.srinivas 0 5 JE/AB/WWS/GTPL/SCR

- 4.1 2 54kg/cm kg/cm2

EXH

R-CHARGER

QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

5

kg/cm2

CR 5 0

5

2 5 kg/cm DROP

RELEASE

Created by

3-PR.VALVE

0 kg/cm2 U-CTLR

EXH

A-CTLR

MAX.LR

MIN.LR

B C

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR 4.9 4.8 4.7

5 kg/cm 4.9 2 4.8 4.7 kg/cm2

EXH

R-CHARGER

4.9 4.8 4.7 5

QRV

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

5

kg/cm2

CR

0.3 kg/cm2 2 5 60 kg/cm in sec.

INSENSITIVITY

Created by

3-PR.VALVE

2 1.5 0 kg/cm kg/cm2

U-CTLR

A-CTLR

0.4

EXH

0.2

MAX.LR

MIN.LR

0.8

B C

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR

4.6 kg/cm22 5 kg/cm

EXH

R-CHARGER

QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

5

kg/cm2

CR 4.4 0.6 kg/cm2 2 5 kg/cm in 6 sec.

SENSITIVITY

Created by

3-PR.VALVE U-CTLR

EXH

A-CTLR

MAX.LR

MIN.LR

EMPTY LOAD

P T

Created by A.srinivas A R JE/AB/WWS/GTPL/SCR EXH

R-CHARGER

QRV

5

BP PRESSURE CR PRESSURE AR PRESSURE BC PRESSURE NO PRESSURE

B C

5

kg/cm2

0.4-2.2 0.6-3.8 0

CR AR

4.8-0

LSD

0.2-55kg kg/cm2 DROP

EK PT

Created by

SPRING PLANK

LOAD SENSING DEVICE

 BOBR/BTAP/BCCW & BLC wagons are provided with' automatic two stage empty load device to cater for higher brake power in loaded condition instead of the conventional manual empty load' device. With the provision of this, brake cylinder pressure of 2.2 kglcm2 is obtained in empty condition  So as to obtain this3.8 a change mechanism and kglcm2over is obtained in called "Load Sensing Device" (LSD) is interposed loaded condition.

LOAD SENSING DEVICE

between the bogie bolster and spring plank. The mechanism gets actuated at a pre determined change over weight and the distributor valve

LOAD SENSING DEVICE LSD

AR

Created by A.srinivas JE/AB/WWS/GTPL/SCR 5 kg/cm2

PT

DV

5 kg/cm2 SPRING PLANK

2.2 3.8 BC

CPB

C R

BP 5 kg/cm2 Created by srinivas

In loaded condition the operating valve lets the Load Sensing Device (LSD) consisting ofELoperating Another flexible hose is connected between port of compressed air signal tomounted EL port distributor valve pipe bracket valve and spring buffer on the bogie and pipe with distributor valve pipe bracket andof operating valve. The operating and the transformer gets the command andenters the brake flexible hoses Compressed airpneumatic from auxiliary into valve remains closed in empty condition. Thusreservoir no pneumatic signal

BLC-DOUBLE CHECK VALVE

Created byCONTAINER A.srinivas JE/AB/WWS/GTPL/SCR BLC WAGON 5 kg/cm2

AR

SPRING PLANK

AR

PT

DV

CPB

C R

2.2 3.8

BC

LSD

LSD

N1

SPRING PLANK Created by srinivas

BLC-DOUBLE CHECK VALVE

Created by CONTAINER A.srinivas CONTAINER JE/AB/WWS/GTPL/SCR BLC WAGON

5 kg/cm2

SPRING PLANK

AR

PT

DV

CPB

C R

2.2 3.8

BC

LSD

LSD

AR

N1

5 kg/cm2

4 kg/cm2

SPRING PLANK Created by srinivas

BLC-DOUBLE CHECK VALVE

Created by A.srinivas CONTAINER

JE/AB/WWS/GTPL/SCR BLC WAGON

5 kg/cm2

AR

AR

SPRING PLANK

PT

DV

CPB

C R

2.2 3.8

BC

LSD

LSD

N1

4 kg/cm2

SPRING PLANK Created by srinivas

AUTOMATIC PRESSURE MODIFICATION {EL-60 VALVE}

EMPTY

APM RESERVIOR

BC 1

DV

CPB

3.8

APM

BC 2

2.2

Created 104mm by A.srinivas JE/AB/WWS/GTPL/SCR SENSOR ARM

Created by srinivas

AUTOMATIC PRESSURE MODIFICATION:1.APM device is interposed between bogie side frame of Casnub bogie and the under frame of wagons. 2.APM should sense the gap only at the time of air

LOAD

APM RESERVIOR

BC 1

DV

CPB

3.8

APM

BC 2

3.8

Created by A.srinivas JE/AB/WWS/GTPL/SCR

Created by srinivas

AUTOMATIC PRESSURE MODIFICATION:-

It restricts the brake cylinder pressure coming from the Distributor valve to 2.2 ± 0.25 Kg/cm 2 in empty condition of the wagon and allows the brake cylinder pressure of 3.8 ± 0.1 Kg/cm2 in loaded condition of the wagon. The factory setting for the movement of the sensor point is 104mm which is consisting of loaded & empty zone. First

BOGIE MOUNTED BRAKE SYSTEM

BOGIE MOUNTED BRAKE SYSTEM COAC FP HOSE

DC

COAC

6kg/cm2

Created by A.srinivas JE/AB/WWS/GTPL/SCR ISOLATING COCK

FP HOSE

FP

DC

5kg/cm2 3.5kg/cm BP BP

COAC BP HOSE

BP HOSE

COAC

CPB

6

kg/cm2

NRV AR 100 LTRs

DV

3.8

BP HOSE

APM

T FLANGE

(WITH OUT PT)

APM RESERVIOR

ISO.COCK WITH VENT FLEXIBLE HOSE PIPE

Created by srinivas

10” BC FOR BOGIE 2

EMPTY LOAD

2.2

3.8

10” BC FOR BOGIE 1 (WITH HANDBRAKE CABLES)

BMBS-BRAKE CYLINDER GASKET PISTON INDICATOR ASSLY.

Created by A.srinivas JE/AB/WWS/GTPL/SCR BC PIN

COMPR.SPRING 3

LOCKING STUD

CLUTCH

COMPENSATOR SAB SPRING

COMPR.SPRING 1 COMPR.SPRING 2

RAM ASSEMBLY Created by srinivas

The brake cylinder receives pneumatic pressure from auxiliary reservoir after being regulated through the distributor valve and APM device. Brake cylinder develops mechanical brake power by outward movement of its piston with ram assembly.

BMBS-BRAKE CYLINDER BC PRESSURE

STROKE Created byPISTON A.srinivas 54+/-10mm JE/AB/WWS/GTPL/SCR

Created by srinivas The piston rod assembly is connected to the brake shoes through a system of rigging arrangement to amplify and transmit the brake power. The compression spring provided in the brake cylinder brings back the ram thus the rigging is also brought to its original position when brake is released.

BMBS-BRAKE CYLINDER BC PRESSURE

Created by A.srinivas JE/AB/WWS/GTPL/SCR

Created by srinivas

The built-in slack adjuster compensates for the wear ofasbrake blocks This The brake ensures cylinder that every has time got aevery double time acting the brake slack application adjuster takes a result place,sufficient the during the brake through equivalent pay-out. For a pry bar actuator brake force ofapplication is brake delivered cylinder on the willwheels. continue Thetobrake movecylinder out tillpaying-in, compensates all the slack infor the anyis applied between the shoe and wheel the rigging is pushed in. system in change is gap takebetween care offbrake and brake reaction block and force wheel ofand the through wheels theisinbuilt encountered. slack adjuster.

BOGIE MOUNTED BRAKE SYSTEM

SECONDARY BEAM

BK.BLOCK BELL CRANK LEVER

VIEW

W H EE L SE T

P U S H R O D s

PRIMARY BEAM

Created by A.srinivas BMBS DOUBLE BOGIE JE/AB/WWS/GTPL/SCR ACTING TOP

BC PIN

EYE PIN CLEVIS PIN Created by srinivas

BOGIE MOUNTED BRAKE SYSTEM

Created by A.srinivas BMBS BOGIE JE/AB/WWS/GTPL/SCR TOP VIEW

Created by srinivas

BOGIE MOUNTED BRAKE SYSTEM NEED FOR ADOPTION OF BMBS IN FREIGHT STOCK: 

In order to overcome the problem faced in conventional bogie breakage, missing components and malfunctioning of SAB. In BMBS fitted wagons, BC is equipped with in

built SAB. In conventional BOXN/BCN wagons due to frequent theft of control rod, main pull Rod, End pull rod & Brake Rigging parts in tripling operation of wagons causing poor brake power in Rakes, resulting Detentions of wagons. In BMBS, wagons

these Items are eliminated. In order to Improve Mechanical efficiency of brake power.  In a Normal Rake of BOXN wagon Fitted with conventional type brake system there was around 18% Brake fading after a trial run of

BOGIE MOUNTED BRAKE SYSTEM NEED FOR ADOPTION OF BMBS IN FREIGHT STOCK:  Braking distance of conventional Rake of 58 +1 wagons of BOXN is 1350 m. However in BMBS wagons it is 880 m (approx).

 In conventional wagons setting of ‘A’ Dimension was a major problem. If any change made in sleeve nuts of E/L device that may create to heavy loss of wagon creating brake binding / wheel skidding. In order to overcome this, BMBS fitted wagons came into field which contains in built slack adjuster.  In case of BMBS system Automatic Load sensing

Device is used which Gives 2.2Kg/cm2 Pressure to brake cylinder during empty condition 3.8 Kg/cm2 pressure during loaded for avoiding the above Problems.

BOGIE MOUNTED BRAKE SYSTEM SILENT FEATURES Use of two no’s. of 10” dia brake cylinders with automatic load sensing device & vent isolating cocks. Use of 58 mm thick K type non asbestos composite brake block. A constant 56 mm piston stroke is required to maintain uniform and efficient braking performance. Application of loads is at the ends the brake beam instead of centre resulted no chances of bending of brake beams. Cylinder is with double acting slack adjustment feature with constant piston stroke resulting in uniform brake performances even as the brake shoes and wheels wears. Total slack adjusting capacity is 500 mm including brake block wear, wheel wear and all clearances.

BOGIE MOUNTED BRAKE SYSTEM SILENT FEATURES All cylinders are equipped with an automatic piston stroke indicator. Replacement of the brake head is quickly and easy by removal by only one pin. Provision of mechanical hand brake system with the use of two no’s stainless hand brake cables pulled through standard hand brake rigging. Easy fitment of bogie mounted cylinder on any standard bogies without making any modifications. Cylinder is mounted parallel to the brake beam and transfers forces through the bell cranks. Improves the efficiency and alignments of the braking forces with the wheels which reduced the wear of shoes and wheels. Use of pressure regulated load sensing device, installed between body and bogie under frame act on 15 psi to maintain normal sensor arm travel of 95 mm.

BOGIE MOUNTED BRAKE SYSTEM DISADVANTAGES The system requires special parts for working such as push rod, bell crank lever, hand brake cable,BC indicators & etc, which are not easily available and very costly. Bk. Cylinder fails working even if there is a very small defect noticed in distributor valve / if DV releasing time slightly more / if APM failed. This type of wagon can not be mixed with a normal rake of conventional type. More wear & tear is noticed near eye hole in push rod. High skilled worker are required for maintenance of these wagons.

SINGLE WAGON TEST RIG

BMBS-SINGLE WAGON TEST RIG Couple up all Brake Gear Fittings properly. Move SWTR near to the Wagon and connect Brake Pipe of the Wagon to SWTR. Dummy the other ends of the Brake Pipe & feed pipe at Palm ends of the Hose Pipe. Fit a BC Pressure Gauge on APM Device.

Connect SWTR to the main source of Air Compressor with 8 - 10 kg/cm2 capacity. Set the Pressure Regulator to 5kg/cm2 & 6kg/cm2 for BP & FP respectively. Open the Cut off Angle Cocks on both ends

BMBS-SINGLE WAGON TEST RIG Keep Brake Valve in charging position and charge the Wagon at Brake Pipe Pressure of 5 ± 0.1 kg/cm2. If there is drop in pressure, locate the leakage with Soap Water and arrest it by changing the "O" Ring. To check the leakage in Brake Pipe close the cocks for 1 minute and then open them. Allow leakage of 0.1 kg/cm2 for 1 minute. Bring Brake Valve in position for full service application. Brake should apply with a pressure drop in BP by 1.3 to 1.6 kg/cm2 in 18 to 30 secs. Record time for filling air to the maximum pressure in Brake Cylinder of 3.8 ± 0.1kg/cm2.

BMBS-SINGLE WAGON TEST RIG Record piston stroke for BMBS cylinder. It should be 50 + 6 mm for Empty and 62 + 6 mm in loaded condition. BUT latest modification (sp.no:WD-23-BMBS-08) ONLY TESTED IN EMPTY54+/- 10mm(i.e. BC PRESSURE-2.2kg/cm2) During the normal condition (without lifting the sensor arm) the brake cylinder pressure should be 2.2 + 0.1 Kg/cm2. During the loaded condition,lift the sensor arm of APM device by using 25mm packing piece. the brake cylinder pressure should be 3.8 +/- 0.1 Kg/cm2. Bring Brake Valve position to Release position. The brake release time should be within 45 to 60 secs. Ensure if the Brakes are completely released and Piston regained to its original position.

BMBS-SINGLE WAGON TEST RIG Check leakage in B.C. for 5 minutes. Keep Brake Valve in charging position and charge the Wagon at Brake Pipe Pressure of 5 ± 0.1 kg/cm2,. For Sensitivity Test, operate the Brake Valve for a BP pressure drop of 0.6 kg/cm2 in 6secs. and check for the application of Brakes. It should apply within 6 secs For In Sensitivity Test, operate the Brake Valve for a BP pressure drop of 0.3 kg/cm2 in 60secs. and watch for the application of Brakes. It should not apply even for 60 secs. Ensure if the Brakes are completely released and Piston regained to its original position.

RAKE TEST RIG

RAKE TEST RIG Rake Test can be performed by using a portable device called “RAKE TEST RIG”. The test rig provides all facilities like a locomotive to conduct the test. The rake test rig has air supply and mobile test rig. The mobile test rig is having a cubical structure and is mounted on wheels. It can be taken to the yard.

A rake consisting of 60 wagons can be tested with this rig. This rig may be used for testing the train in yard before attaching the engine.

RAKE TEST RIG

The procedure is as follows: A. Prepare set up (Rig) for Rake Test. B. Carry out Visual Examination. C. Conduct Leakage, Service Application and Release Test.

A.Prepare set up (Rig) for Rake Test:• Place a board “DANGER - MEN AT WORK” on either side of the formation for safety. • Connect RTR to the main source of Air Compressor with 8 - 10 kg/cm2 capacity. • Set the Pressure Regulator to 5 kg/cm2 & 6 kg/cm2 For BP & FP respectively. • Couple the BP & FP to the first wagon of the rake. B. Carry out Visual Examination:Visually inspect by coupling the BPs &

RAKE TEST RIG Ensure that hand brakes of all wagons are fully released (i.e. OFF position). Ensure that operating handle of empty load box is in correct position (i.e. EMPTY position).

Ensure that the isolating cock on DVs of all wagons are in open position (i.e. vertical position).

RAKE TEST RIG Ensure that the isolating cock of feed pipe of all wagons are in open position (i.e. horizontal position).

Ensure that the non return valve(check valve) of feed pipe of all wagons are in right direction. Inspect loose suspension brackets and anti-pilferage devices of all air brake subassemblies. In case of BOBRs inspect the primary & secondary locks.

RAKE TEST RIG Visually inspect for any problem/damage in the brake pipe, hose pipe, coupling , COACs & etc.

Ensure that BP & FP hose couplings are connected to form a continues air passage from the test rig to the last vehicle. for proper identification BP & FP coupling heads are marked with “BP”- “FP” and painted in green & white respectively. in no case ,a FP should be connected to the BP any where in the train or vice versa.

RAKE TEST RIG Ensure that cut-off angle cocks of brake pipe and feed pipe at the rear end of train are kept closed. Provide the pressure gauges for BP & FP are in the brake van. Ensure that quick couplings are attachable & detachable.

The drop in brake pipe pressure gauge shall not be more than 0.25 kg/cm2 per minute.

RAKE TEST RIG C. Conduct Leakage, Service Application and Release Test. Examine for leaky components, malfunctioning of distributor valves, brake cylinders, control and auxiliary reservoirs, angle cocks, BP hoses. In case of BOBR,BCCW,BLC & BTAPs Examine the LSDs. Rectify or replace the problematic part/subassembly. If the leakage rate is more then the value indicated (0.25 kg/cm2 per minute) check for excessive leakage on individual wagon as indicated below: A hissing sound would be audible at points where leakage is heavy.. Once the hissing sound is heard from a particular area, pin point the location of leakage by applying soap water solution. Use of permitted material viz. Teflon tape for arresting the leakage at threaded joints.

RAKE TEST RIG Service Application:1.Bring Brake Valve position for service application. Brake should apply with a pressure drop in BP by 0.9 kg/cm2 in 18 to 30 secs. 2.Observe the BC piston rollings for 1 hour. 3.if rollings are found, check leakage from the CR “O” rings/CR dummy/BC front cover/BC dummy/ BC branch pipe for arresting leakage. 4.use Teflon tape for arresting the leakage at CR & BC dummy nuts.

RAKE TEST RIG Full Service Application {1.5kg/cm2}:Record the Piston Stroke of Brake Cylinders. It should be a following lengths.

(BVZI- 45 mm+/- 10)

/BOBYN

RAKE TEST RIG Full Service Application {1.5kg/cm2}:1.In case of BMBS cylinder. It should be 50 + 6mm for Empty and 62 + 6mm in loaded condition.

but latest modification (sp.no:WD-23BMBS08) ONLY TESTED IN EMPTY i.e. 54+/-10mm. 2. Ensure that piston stroke under empty & loaded conditions are within the specified limits. 3. Ensure that the brake shoes of each wagon are mating the wheels when brakes are applied.

RAKE TEST RIG

Release Test:-

1.Bring Brake Valve position to Release position. 2. The brake release time should be within 45 to 60 secs. 3. Ensure if the Brakes are completely released and Pistons are regained to its original position. 4.The drop in brake pipe pressure gauge shall not more than 0.25 kg/cm2 per minute at the Brake van. 5. Manually release the quick release valves of all wagons for Attaching the engine.

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