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Handbook on Maintenance of BMBC for ICF/RCF of 41

(For official use only)

DRAFT

(Govt. of India)

(Ministry of Railways)

HANDBOOK ON

MAINTENANCE OF

BOGIE MOUNTED BRAKE CYLINDER

(BMBC) IN ICF/RCF DESIGN COACHING

IRCAMTECH/2016/Mech/BMBC/1.0

Aug 2016

MAHARAJPUR, GWALIOR -474005 egkjktiqj Xokfy;j 474005


Foreword

This Maintenance hand book has covered introduction, constructional

details, instructions and precautions during inspection and maintenance of

Bogie Mounted Brake Cylinder (BMBC). Wherever required, sketches and

colored photographs have been provided to make the understanding clear.

I am sure that this maintenance handbook will be useful to the concerned staff

to ensure trouble free service of Air Brake System in ICF/RCF design

coaches.

Technological up-gradation and learning is a continuous process. Hence

feel free to write us for any addition / modifications or in case you have any

suggestion to improve the Hand Book, your contribution in this direction shall

be highly appreciated.

We welcome any suggestion for addition and improvements from our readers.

Place: CAMTECH/GWL (A R Tupe )

Date: 11.08.2016 Executive Director

CAMTECH/GWL


PREFACE

Air Brake System is an important part in Coaches considering functional &

operational safety. Bogie Mounted Brake Cylinder plays a vital role in efficient

braking in Bogie Mounted Brake System of ICF/RCF design Coaches. The

maintenance & Component details of Bogie Mounted Brake Cylinder (BMBC)

for coaching stocks are given in this handbook.

The purpose of this maintenance hand book is to enhance knowledge and

competence of Workshop & C&W staff in dealing with Air Brake System in

coaching stock maintenance.

This hand book is aimed at assisting concerned staff and does not supersede

any existing instructions from Railway Board, RDSO, IRCA or OEMs etc. Most

of data and information mentioned herein are available in some form the other

in various books and OEMs manuals. If any changes are made, these will be

used in the form of correction slips. For convenience, this book includes a

proforma for entering all correction slips serially.

Technological up gradation and learning is a continuous process. Hence feel

free to write us any addition / modification in this handbook or in case you have

any suggestion to improve the handbook. Your contribution in this direction will

be appreciated.

Date:11.08.2016

(K.P. Yadav) Director/ Mech. CAMTECH/GWL


Contents

S. No Description Page No

Foreword 3

Preface 4

PART A- BMBC WITH BUILT IN DOUBLE ACTING SLACK

ADJUSTER

1 Introduction 9

2. Scope 9

3. Salient features & advantages 9

4. Types of brake cylinders 11

5. Construction & working 12

6. Brake cylinder assembly. 14

7. Installation on bogie. 16

8. Brake block changing procedure & slack adjuster re-setting. 16

9. Performance requirements 17

10. Material & workmanship 18

11. Dimensions and tolerances 18

12. Tests 18

13. Warranty 19

14. Painting 19

15. packing 19

ANNEXURE-A 20

ANNEXURE-B 22

PART B- BMBC WITH BUILT IN SINGLE ACTING SLACK

ADJUSTER

1. Introduction 25

2. Maintenance of Bogie Mounted Brake Cylinders 26

3. Cleaning and inspection 29

4. Assembly 30

5. Testing procedure 32

6. Important instructions for reassembling the brake cylinder at the

workshops

33

7. Calculated the percentage of braking and the force available on

each brake for the bogie mounted AC Coach.

35

8. Brake power calculations 36

9. Special tools 40


PART –A

BOGIE MOUNTED BRAKES

CYLINDER WITH BUILT IN

DOUBLE ACTING SLACK

ADJUSTER


1. INTRODUCTION

At present ICF type main line conventional coaches have been provided with

203 mm single acting Bogie Mounted Brake Cylinder. Railways have reported

that the piston stroke of 203 mm size BMBC on ICF coaches gets reduced up

to 20 mm from the pre-set value of 32 mm in every trip. This necessitates

readjustment of piston stroke in each trip by the maintenance staff. Sometimes,

frequent brake binding on GS and SLR coaches is also reported. This problem

is limited to GS & SLR coaches due to dense loading in these coaches,

therefore, huge variation in tare and loaded weight is observed. The reason

can be attributed to single acting slack adjuster used in BMBC which allows the

piston rod to pay out in loaded condition this is not allowed to go back due to

absents of pay in mechanism when the coach becomes empty. This is why

need of Bogie Mounted Brakes Cylinder with built in double acting slack

adjuster for BG main line coaches has been arises.

2. SCOPE

2.1 This Functional requirement specification covers the technical requirements

related to manufacture, supply, performance and testing of Double acting

Bogie Mounted Brake cylinder for ICF design BG Mainline coaches.

3. SALIENT FEATURES & ADVANTAGES

1. Brake Cylinder with integral double acting slack adjuster.


2. No change required in existing arrangement.

3. Automatically maintains a constant piston stroke. No need to adjust the brake

cylinder stroke intermittently, whenever there is change in the gap between the

wheel and brake blocks.

4. Hand Brake attachment suitable for existing system.

5. User friendly, No need to adjust the piston stroke after brake block changing.


4. Types of Brake Cylinders:

THERE ARE TWO VERSIONS OF BRAKE CYLINDERS AVAILABLE.

A. BRAKE CYLINDER WITHOUT HAND BRAKE ATTACHMENT.

THESE BRAKE CYLINDERS SHALL BE USED ON GS PASSENGER COACHES,

OTHERS THAN SLR COACHES.

B. BRAKE CYLINDER WITH HAND BRAKE ATTACHMENT

THESE BRAKE CYLINDERS SHALL BE USED ON SLR COACHES.


5. CONSTRUCTION & WORKING

Air from the Distributor valve (DV) goes into the Brake Cylinder through the hose

connection to the brake cylinder. The air pushes the piston assembly forward

against the compression springs (piston return & slack adjuster). This causes the

RAM assembly to move forward till the bearing contacts the Tube Ring i.e. as the

Brake Shoes touch and apply the brake force on the wheels. The clutch head on

the compensator screw remains engaged with the Front Female clutch on the

piston. Thus there is no extension of the RAM assembly on the compensator

screw. The internal construction (springs, location of Tube Ring etc.) ensures that

the stroke of the brake cylinder is constant when no slack adjustment is there.


When the Brake Shoes and the Wheel has worn out then the gap between the

wheel and the shoe is created. When the air from the Distributor valve (DV) goes

into the Brake Cylinder the piston assembly moves forward. It moves beyond the

control distance as the slack is there (there is no restraint to the ram extension).

As the piston moves beyond the control distance the bearing gets in contact with

the Tube Ring.

As the piston still moves forward the compression spring in the clutch assembly

side gets compressed thus disengaging the compensator screw clutch head. This

allows the RAM assembly to extend due to the force exerted by the RAM

compression spring till the point the slack is taken up and the reaction force is

encountered. Thus the Brake Shoe comes in contact with the Wheel. After, the

slack had been accommodated; the brake cylinder functions normally giving a

constant stroke.

The inbuilt slack adjuster is double acting. If one wants to retract the slack

adjuster one should apply force on the RAM side. This allows the RAM to collapse

moving in the compensator screw. This can also be achieved by rotating the RAM

on the compensator screw.


6. BRAKE CYLINDER ASSEMBLY:


ITEMS NO POS NO GET DESCRIPTION

506604 49 0 410 GREAS ARE M 914

453831 48 1 SEALING RING

451533 47 1 SCREW PLUG

I. H. 0062 46 2 SPRING WASHER

477324 45 4 SPRING WASHER

C155183 44 1 RAM LINK

777776 43 1 SPRING COMPERESSION

469541 42 4 HEXAGON NUT

463754 41 4 HEX_HEAD BOLT

765218 40 1 SPRING COMPRESSION

772262 39 2 WIPER RING

A3994173 38 2 THREAD CAP

764395 37 4 SPRING COMPRESSION

755559 36 2 O-RING

765627 35 2 PLUG

736839 34 4 SCREW, DRIVE

C143269 33 1 NAMEPLATE. TMB-60

734491 32 4 NUT. HEX

735734 31 4 WASHER. LOCK

768330 30 4 BOLT, TEE HEAD

1195097 29 1 BREATHER ASSEMBLY

734734 28 1 SCREW, HEX HEAD

776520 27 1 GASKET

769953 26 1 WIPER RING

765823 25 1 SPACER

451632 24 1 MACHINE SCREW

1171614 23 1 RAM ASSEMBLY

C143268 22 1 SPRING. RAM

747847 21 4 SELF LOCKING SET SCREW

765847 19 1 RETAINING RING

765846 18 1 RING TUBE

1171864 16 1 NON-PRESSURE HEAD AS.

1171924 15 1 SPRING TUBE ASSEMBLY


C155786 13 1 CUP. BEARING


764084 11 1 BEARING

C198392 9 4 SCREW, FLAT HEAD

765814 8 1 CLUTCH. FRONT FEMALE

1171925 7 1 SCREW ASSEMBLY

C198391 6 1 SCREW, FLAT HEAD

765809 5 1 CLUTCH, BACK FEMALE

C142735 4 1 8” PACKING CUP

C142734 3 1 GUID RING, PISTON

1171612 2 1 PISTON ASSEMBLY 8”

1199279 1 1 HOUSING


7. Installation on the bogie:

MOUNTED ON THE BOGIE WITH FOUR BOLTS ON THE AVAILABLE HOLES.

CONNECTED TO THE DISTRIBUTOR VALVE, BC PIPE THROUGH A ½“FLEXIBLE HOSE.

CONNECTED TO THE BOGIE RIGGING THROUGH EXISTING PIN.

BRAKE CYLINDER WITH HAND BRAKE ATTACHMENTS, CONNECTS TO THE EXISTING

HAND BRAKE ARRANGEMENT.

8. Brake block changing procedure & slack adjuster re-setting.

8.1 Brake blocks changing procedure:


Brake block changing is simple as no adjustment in brake cylinder is required. It

can be done by inserting a pry bar between brake block & wheel from side of

coach. By manual pushing the brake block through pry bar, slack adjuster of

brake cylinder moves inside, thus creating adequate space for removal of old

block & replacing of new brake block. This procedure is repeated for changing all

brake blocks.

8.2. Slack adjuster re-setting:

Slack adjuster re-setting is automatic.

Slack adjuster manually pushed inside

for changing brake blocks. After

changing of brake blocks, when brakes

are applied slack adjuster moves out till

blocks touches on wheel & brakes are

applied. During release of brake it

adjusts to maintain gap between wheel

& brake block. After 2-3 brake

application & release it maintains a

constant specified gap.

9. PERFORMANCE REQUIREMENTS

9.1 The double acting brake cylinder is to be so designed that it provides faultless

operation under the Indian Railway environmental conditions for a period of at

least 6 years from the date of commission.

9.2 The double acting brake cylinder should be designed in such a way that it has

minimum wear and tear and maintenance possibility.


10. MATERIAL & WORKMANSHIP

10.1 The material of brake cylinder with in-built slack adjuster shall confirm to the

latest revision of Collaborator / RDSO approved drawing.

10.2 All the components shall be manufactured/ procured to the material

specification indicated against each component in the drawings.

10.3 The castings shall be sound, clean and sharp without defects or blemishes

of any kind and conform to the requirement of the specification.

10.4 The rubber item shall be smooth, free from pin holes, blisters, porosities and

other visual flaws.

10.5 The fabrication and welding of fabricated cylinder body shall conform to the

requirements of Section-II of IS: 2825 (code for unfired pressure vessel).

10.6 Fabrication, welding of other items shall be carried out in accordance with

the procedure laid down in RDSO pamphlet no. G-72 (Rev. I).

11. DIMENSIONS AND TOLERANCES

11.1 The dimensions and tolerances of brake cylinder shall be as indicated in the

latest revision of drawings as indicated in the approved drawings.

11.2 All critical dimensions identified in the drawing shall be gauged. The

manufacturers shall have the necessary gauge available with them.

12 TESTS

12.1 Type Test

The following test shall constitute type test and shall be carried out in

accordance to Annexure - B at the time of Product approval:

a) Performance and Endurance Test

12.2 Routine Test

12.2.1 Leakage & Function Test for Brake Cylinder Complete


The leakage and function test of the brake cylinders should be conducted in

accordance with Annexure-A.

a) Hydraulic Test

This test shall be conducted on cylinder body. The cylinder body shall be

subjected to hydraulic pressure of 7 Kg/cm2 for 5 minutes. There should be no

leakage.

13. WARRANTY

13.1 The firm shall, at his cost, replace the double acting brake cylinder failing

13.2 prematurely or proving unsatisfactory in service for reasons attributed to

defective / faulty design, defective material or poor workmanship within a

period of 30 months from the date of delivery or 24 months from the

date of fitment, whichever is earlier. This warranty shall survive, not

withstanding the fact that the double acting brake cylinder may have

been inspected, accepted and payment thereof made by the

PURCHASER.

14. PAINTING

14.1 The exterior of the brake cylinder shall be painted with black enamel paint.

15 PACKING

15.1 The manufacturer shall ensure that all external ports of brake cylinders are

suitably covered with protection caps to prevent ingress of foreign particles during

handling and storage.

15.2 The manufacturer shall also ensure that brake cylinders in assembled condition

are adequately packed before dispatch to prevent damage in handling and

storage.


ANNEXURE - A

TESTING PROCEDURE OF BOGIE MOUNTED BRAKE CYLINDER WITH

BUILT IN DOUBLE ACTING SLACK ADJUSTER

S.

No.

Description of Tests Specified Values

1 Leakage Test (Room Temperature)

a Check brake cylinder leakage at 0.8

Kg/cm2 air pressure

Leakage should not exceed 0.1

Kg/cm2 in 10 min.

b Check brake cylinder leakage at 3.8

Kg/cm2 air pressure

Leakage should not exceed 0.1

Kg/cm2 in 10 min.

2 Maximum Slack Adjustment Take-up

a Apply 0.7 Kg/cm2 air pressure and

allow the ram to extend out

completely.

305 mm (Minimum)

3. Constant Piston stroke Test at 0.8 kg/cm2 (Stopper plate at 100 mm

from initial position)

a Forward slack adjuster take-up.

Increase the gap between the brake

cylinder front end and the stopper

plate.

After application and release of

BC

pressure, the gap between the

brake cylinder front end and the

stopper plate should remain

constant.

b Backward slack adjuster take-up.

Decrease the gap between the brake


plate.


BC




constant.

4 Constant Piston stroke Test at 3.8 kg/cm2 (Stopper plate at 100 mm


a Forward slack adjuster take-up.



plate.


BC pressure, the gap between

the brake cylinder front end and

the stopper plate should remain

constant.


b

Backward slack adjuster take-up.



plate.





constant.



A Forward slack adjuster take-up.



plate.


BC pressure, the gap between the



constant.

B




plate.





constant.



A Forward slack adjuster take-up.



plate.


BC pressure, the gap between the



constant.

B




plate.


BC




constant.


ANNEXURE-B

TESTING PROCEDURE OF BOGIE MOUNTED BRAKE CYLINDER WITH

BUILT IN DOUBLE ACTING SLACK ADJUSTER

(TYPE TESTING –ONCE A YEAR)

Leakage Test for Brake Cylinder complete

Apply 0.7 Kg/Cm2 & 3.8 Kg/Cm2 air pressure and wait 5 minutes after application

and observe that the leakage is not more than as given in table below.

Brake Cylinder Pressure Temp * Maximum leakage rate

-10o C 0.07 Kg/Cm2 in 10 minutes

0.7 Kg/Cm2 21o C 0.03 Kg/Cm2 in10 minutes

55o C 0.03 Kg/Cm2 in10 minutes

-10o C 0.03 Kg/Cm2 in10 minutes

3.8 Kg/Cm2 21o C No. leakage in 10 minutes

55o C No. leakage in 10 minutes

Cycle Test/ Endurance Test

After Leakage & Performance test for brake cylinder successfully completed, cycle

the brake cylinder at a pressure of 6.2 Kg/Cm2 for 200,000 cycles at room

temperature.

Efficiency at the completion of cycle test / endurance test must not decrease more

than 2% when subjected to leakage & environmental test after the cycle test at room

temperature.


PART –B

BOGIE MOUNTED BRAKES

CYLINDER WITH BUILT IN SINGLE

ACTING SLACK ADJUSTER


1. Introduction

The Bogie Mounted Brake Cylinders are provided with an in-built slack adjuster to

maintain a constant brake block clearance automatically. It is a single acting

slack adjuster by which the clearance between wheel and brake block can be

decreased automatically by increasing the effective length of piston rod whenever

the piston stroke exceeds up to 32mm due to wear on the brake block and the

wheel. During return stroke, the adjusting movement takes place.

If the clearance between wheel and the brake blocks is less due to any reason, it

does not bring the required clearance automatically.


Differentiate Between Maximum Stroke and Working Stroke of Bogie

Mounted Brake Cylinder

Maximum Stroke: This is the stroke beyond which the piston cannot come

outward. It is up to 32 mm for coaching stock.

Working stroke: This is the stroke at which, the in-built slack adjuster increases

the effective length of the piston rod automatically whenever the clearance

increases due to wear on the brake block and the wheel. It is up to 32 mm for

coaching stock.

2. MAINTENANCE OF BOGIE MOUNTED BRAKE CYLINDERS

(RDSO sketch. 81200) gives the details of brake cylinders and the part number

list is indicated in the table.

Dismantling

i) Unscrew cross head and adjusting tube sub-assembly.

ii) Loose jubilee clips and remove dust excluder and bush.

iii) Admit compressed air in brake cylinder, unscrew grub screw. Vent

compressed air and unscrew collar by using C-spanner. remove hand brake

trunion.

iv) Unscrew hex nuts M12 slowly. Please note that release spring compressed

with force of 60 kg. Note: The release spring exerts severe force while

dismantling the unit, the front cover should be removed very carefully. The

dismantling can not be done by a single person. Atleast two persons are

necessary.

v) Remove front cover, release spring, piston trunk sub-assembly with trunion

body and ratchet with adjusting screw.

vi) Remove split pin, pin and rocker arm.

vii) Remove allen bolts and piston and piston trunk sub-assembly. Please not that

piston and piston trunk sub-assembly are matched pair and are not

interchangeable. Always put some identification mark.

viii)Remove circlip, collar , ratchet with adjusting screw, pawl, pawl spring,

Plunger, turnion body, thrust washer.

ix) Remove Piston packing from piston.


203 mm Air Brake Cylinder With Slack Adjuster


Section A-A of 203 mm Air Brake Cylinder With Slack Adjuster


3. Cleaning and Inspection

Wash all the parts in suitable cleaning fluid and wipe them carefully. Inspect pawls,

Pawl housing ring, ratchet, tooth rollers, roller plate, thrust washer for wear and

damage. Inspect threads of ratchet with adjusting screw and adjusting tube for the

possible damage. Replace packing. Check all the springs for possible corrosion and

distortion. It is advisable to change the springs on every POH. Give all other parts a

thorough visual inspection to detect apparent defects. Replace worn or damaged

parts.

Item Description &

dimensions

No.

off

Ref. Drg. Mtl. &

spec.

Remarks

1 Cylinder Body 1 SK-81201 Item 1, 3,4 & 5

2 Piston 1 SK-81203 Item - 1

3 Piston packing 1 SK-81204 Item -10

4 Plunger 1 SK-81206 Item - 2

5 Circlip Light B22 1 - IS:3075 Galv.

6 Special Washer 1 SK-81206 Item-14

7 Plunger Spring 1 SK-81206 Item-18

8 Piston Trunk 1 SK-81204 Item-1 & 2

9 Tee bolt M12x35

Alternatively

M12x45

4 - Galv.

10 Hex. head nut

M12

4 - IS:1363 Galv.

11 Spring washer

M12 type A

8 - IS:3063 Galv.

12 Dome cover 1 SK-81202 Item-1

13 Ratchet with

adjusting screw

1 SK-81204 Item-9

14 Adjusting tube 1 SK-81204 Item-6, 7 & 8

15 Release Spring 1 SK-81206 Item-20

16 Guide bush 1 SK-81202 Item-2

17 Hand brake

trunnion

1 SK-81205 Item-12


18 Split pin 5 x 40 3 - IS:549 Galv.

19 Washer M22 type

-C

3 - IS:2016 Galv.

20 Slotted head grub

screw 'C' M6x6

2 - IS:2388 Galv.

21 Jubilee clip size-5 1 - Galv.

22 Dust excluder 1 SK-81204 Item-11

23 Latch 1 SK-81206 Item-3

24 Latch spring 1 SK-81206 Item-21

25 Ring 1 SK-81206 Item-23

26 Slotted Nut 7/8"

B.S.W.

(20 mm high)

1 - Galv.

27 Shims for plunger As

requir

ed

SK-81206 Item-16

28 Special washer 1 SK-81206 Item-12

29 Trunion Body 1 SK-81205 Item-1

30 Coller 1 SK-81206 Item-4

31 Circlip light A32 1 - IS:3075 Galv.

4. Assembly

After cleaning and inspection of all the parts and before re-assembly apply

uniform layer of grease Esso Becon 2 on all the moving parts. Grease cylinder

body and piston packing liberally with Esso Becon 2.

i) Put washer and insert ratchet with adjusting screw in turnion body. Put two

collars in the groove of ratchet with adjusting screw and lock it with circlip.

ii) Insert spring retaining cup plunger spring, washer and internal circlip with

circlip plier in the longer side of trunion body.


iii) Insert pawl (ensure proper position) pawl spring in the square hole of the

trunion body and lock it with strip. Bend the ends of the strip.

iv) Place pawl housing ring on trunion body so that it pivots on the pivot pin of

turnion body. Check that tooth of pawl housing ring matches with teeth of

ratchet with adjusting screw. If required, tooth of pawl housing ring may be

filed.

v) Insert plunger pin with required No. of shims. Insert this sub-assembly in the

shorter side of trunion body.

vi) Place the above sub-assembly (consisting of all the above parts) on piston

(ensure proper position as indicated in the assembly drawing. Place piston

trunk sub-assembly on it and lock it with piston by 4 Nos. allen screw and

spring washer with a tightening torque of 200 kg.cm. Insert packing on

piston.

vii) Insert rocker arm roller pin in roller and then insert it in rocker arm. Insert

roller and washer on the roller side of roller pin and lock it with split pin.

viii) Place rocker arm sub-assembly within two shackles of piston trunk ring sub-

assembly and insert rocker arm pivot pin and washer and lock it with split

pin.

ix) Tighten roller plate with front cover with 8 Nos. hex. bolts spring washers and

hex. nuts .

x) After applying grease Esso Becon 2 on all the moving parts, piston packing,

cylinder body, insert the above sub-assembly (consisting of piston trunk sub-

assembly, piston in cylinder body.

xi) Place release spring on piston trunk sub-assembly.


xii) Place front cover in required position A,B,C on the release spring and

compress the spring with a force of 60 kg approximately. Tighten front cover

with body with 4 Nos. hex. head bolts, spring washer and hex. nut with a

tightening torque of 200 kg cm.

xiii) Place hand brake trunion sub-assembly on piston trunk sub-assembly.

Screw collar on piston trunk sub-assembly and screw in grub screw. Put

latch spring and latch in cross head. Insert ring in the latch.

xiv) Put cross head sub-assembly on adjusting tube sub-assembly consisting of

adjusting tube, adjusting tube screwed and resetting plate). Lock cross head

with adjusting tube sub-assembly by washer, hex. slotted nut and split pin.

xv) Clamp dust excluder on bush with jubilee clip and insert adjusting tube sub-

assembly in bush. Screw adjusting tube sub-assembly in bush. Screw

adjusting tube sub-assembly on ratchet with adjusting screw till it reaches its

dead end.

xvi) Clamp dust excluder on collar with jubilee clip.

xvii) Screw 1/2” plug with O-ring in body.

5. Testing Procedure

The testing procedure of brake cylinder is given below

PREPARATION FOR TEST

The test layout is shown in the attached figure 6.5 (RDSO's Sk 98108). A special

pin will be required to locate the cross head between the angle iron slots. During

testing cock 2 must be opened slowly whenever the cock is used to admit air


under pressure to the cylinder. Connect the air supply to the cylinder body.

Commence with all cocks closed

Test no. 1 Leakage:

Open Cock 1 to charge the MR to 7 kg/cm2 pressure

Open Cock 2 to charge the cylinder 0.7 kg/cm2 pressure

The piston stroke must be limited to 32mm, wait for one minute for settlement

and there must be no drop in pressure shown in the leakage volume gauge for a

further minute. Also observe that leakage does not exceed 0.1 kg/cm2 in 10

minutes.

Repeat this test with the cylinder charged to 3.8 kg/cm2 pressure and with cock

3 closed limiting the maximum piston stroke up to 32 mm. Observe that the

leakage does not exceed 0.1 kg/cm2 in 10 minutes.

Open Cock 3 to exhaust the cylinder pressure to zero.

Test no. 2 - Operation:

A. Full Stroke

Close cock 3 and open cock 2.

Observe the full stroke of the piston.

This must be within 1.0 mm of the maximum stroke value.

B. Take-up Stroke

Close cock 2 and open cock 3 to exhaust the cylinder pressure to zero.


Close cock 3.

Open cock 2 and allow the piston to move out slowly until the operating pawl

is heard to “click over” then close cock 2.

Measure the take up stroke .

This must be 32 mm for main line self generating coaches of 32 mm stroke.


As the cylinder returns to release the locking pawl must be heard to click into

position

Note:

a. Operate the piston at full stroke at least 18 times to test all ratchet teeth.

b. Observe that the adjuster operates at each release and the adjusting

tube and cross head being ‘inched’ out along the stroke.

c. The movement of the Piston must be smooth without any tendency to

stick at any part of the stroke.

RDSO Sk. -98108


Test no.3 - layout for brake cylinder with built in slack adjuster

C. Take-up Length (without Quick Resetting Gear)


Remove the pin from the cross head and unscrew the adjusting tube until the

red resetting mark on the adjusting Tube is visible.

Disengage resetting latch and screw in the Adjusting Tube.

Re-engage resetting latch.

Check that the Dust Excluder Collar is free and does not twist when the

Adjusting Tube is being rotated.


Close all cocks when the system is at atmospheric pressure.

D. Take-up Length (With Quick Resetting Gear)


Remove the pin from the cross head and turn the resetting screw until the red

resetting mark on Adjusting tube is visible.

Screw in the Adjusting Tube with the resetting screw.

Check that the Dust Excluder Collar is free and does not twist when the

Adjusting tube is rotated . Close cock 1 and open cock 2.

Close all cocks when the system is at atmospheric pressure


6. IMPORTANT INSTRUCTIONS FOR REASSEMBLING THE BRAKE CYLINDER

AT THE WORKSHOPS

i) While fixing the Roller plate with front cover 4 pairs of hex. Bolts M 6x25

along with spring washer A6 and hex nut M6 are required. Before fixing the

roller plate, the inner surface of front cover should be checked for perfect

plane. At the time of fixing the roller plate with front cover 2 Nos. of spring

washers are kept inside in between them (one each side) in first two bolts, so

that the rollers can move smoothly in the cover plate in angular position.

ii) While matching the holes of plunger and plunger pin number of shims are

added (say 2 or 3) as per the requirement, in the plunger pin so that spring

Dowel pin Φ2X14 easily locks the plunger and plunger pin by inserting the

dowel pin in the holes.

iii) At the time of re-assembly check that the tooth of pawl housing ring matches

with the teeth of Ratchet with adjusting screw. The pawl housing ring must go

smoothly inside the teeth of Ratchet. If it is not matching then the notch portion

of the tooth of pawl housing ring should be filed till it matches with the teeth of

Ratchet screw.

iv) Before final assembly of piston and piston trunk sub-assembly ensures that

the threads of adjusting tube (turns in clock wise direction) smoothly matches

with the threads of Ratchet screw.

v) Before fixing the front cover in the cylinder body check visually the red paint

mark appears in the Adjusting tube. If it is not visible then repaint.

7. Calculate the Percentage of braking and the force available on each brake head

for the Bogie mounted AC Coach


Technical Data’s

i. Diameter of the cylinder = 20.3cm (8”)

ii. Area of piston (A) = 323.65 cm2

iii. Maximum BC Pressure(B) = 3.8 Kg/cm2

iv. Leverage Ratio of Levers(C) = 366:174

v. No.of Levers per Axle (D) = 2

vi. No of Brake Blocks (N) = 16

vii. Cylinder efficiency (CE ) = 0.9

viii. Rigging efficiency (RE) = 0.9

ix. Tare weight of the coach = 50 Tonnes

SUMMARY

i. Brake force available on each brake head = 1.046 Tonnes

ii. Percentage of braking = 33.472 %

8. Brake Power Calculations:

i. Force available on the piston (F) = (A) X (B)

= 323.65 X 3.8

= 1230 kg

= 1.23 Tonnes

ii. Mechanical advantage/axle (MA) = (C) X (D)

= 366 X 2

174

= 4.2


iii. Theoretical braking force available on an axle

= (F) X (MA)

= 1.23 X 4.2

= 5.166 Tonnes

iv. Theoretical braking force available on a coach = 5.166 X 4

= 20.664 Tonnes

v. Theoretical braking force available on each brake block (TF)

= 20.664 / 16

= 1.3 Tonnes

vi. Actual Brake force on each Brake block (AF) = (TF) X (CE) X (RE)

= 1.3X 0.9 X 0.9

= 1.046 Tonnes

vii. Actual brake force available on a coach = (AF) X (N)

= 1.046 X 16

= 16.736 Tonnes


viii. Theoretical Percentage of braking= Theoretical Braking Force Available on a coach

Tare weight of the Coach

= ( 20.664 / 50 ) X 100

= 41.328 %

ix. Actual Percentage of Braking = Actual Brake force available on a coach

Tare weight of the Coach

= (16.736 / 50 ) X 100

= 33.472 %

Note: In the similar way the brake power of non AC coaches can be calculated by

taking the following Technical data-

Technical Data’s

i. Diameter of the cylinder = 20.3 cm ( 8” )

ii. Area of Piston ( A ) = 323.65 cm2

iii. Maximum BC Pressure ( B ) = 3.8 kg/cm2

iv. Leverage ratio of levers ( C ) = 256 : 134 ( 1.91 )

v. No. of levers per axle ( D ) = 2

vi. No. of brake blocks ( N ) = 16

vii. Cylinder efficiency ( CE ) = 0.9

viii. Rigging efficiency ( RE ) = 0.9

ix. Tare weight of the coach = 37.55 Tonnes


9. Special Tools

Sr. No. Description No. off

1. Ball peen hammer 1/2 kg 1

2. Screw driver big 1

3. Screw driver small 1

4.

5.

Double end spanner to tighten/loosen

M6 nut

1

6.

Press machine to apply 60 kg force

for assembling front cover with body

1

7. Scriber to remove Split pin 1

8. 5 mm Allen key 1

9. Torque wrench with 200 kg cm 1


CORRECTION SLIPS

The correction slips to be issued in future for this handbook will be numbered

as follows:

CAMTECH/2016/Mech/BMBC/1.0/ XX date …………….

Where “XX” is the serial number of the concerned correction slip (Starting

from 01 onwards)

CORRECTION SLIPS ISSUED

Sr.No. of C.Slip Date of issue Page No. and

Item no.

modified

Remarks

on maintenance of bogie mounted brake … handbook on...on maintenance of bogie mounted brake...

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