Post on 23-May-2018
Handbook on Maintenance of BMBC for ICF/RCF Page 1 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
Handbook on Maintenance of BMBC for ICF/RCF Page 2 of 41
Handbook on Maintenance of BMBC for ICF/RCF Page 3 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 4 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 5 of 41
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
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Handbook on Maintenance of BMBC for ICF/RCF Page 7 of 41
PART –A
BOGIE MOUNTED BRAKES
CYLINDER WITH BUILT IN
DOUBLE ACTING SLACK
ADJUSTER
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Handbook on Maintenance of BMBC for ICF/RCF Page 9 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 10 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 11 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 12 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 13 of 41
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.
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6. BRAKE CYLINDER ASSEMBLY:
Handbook on Maintenance of BMBC for ICF/RCF Page 15 of 41
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
764058 14 1 RETAINING RING
C155786 13 1 CUP. BEARING
752543 12 1 RETAINING RING
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
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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:
Handbook on Maintenance of BMBC for ICF/RCF Page 17 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 18 of 41
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
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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.
Handbook on Maintenance of BMBC for ICF/RCF Page 20 of 41
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
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.
4 Constant Piston stroke Test at 3.8 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.
Handbook on Maintenance of BMBC for ICF/RCF Page 21 of 41
b
Backward slack adjuster take-up.
Decrease 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.
5 Constant Piston stroke Test at 0.8 kg/cm2 (Stopper plate at 225 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
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.
6 Constant Piston stroke Test at 0.8 kg/cm2 (Stopper plate at 225 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
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 22 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 23 of 41
PART –B
BOGIE MOUNTED BRAKES
CYLINDER WITH BUILT IN SINGLE
ACTING SLACK ADJUSTER
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Handbook on Maintenance of BMBC for ICF/RCF Page 25 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 26 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 27 of 41
203 mm Air Brake Cylinder With Slack Adjuster
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Section A-A of 203 mm Air Brake Cylinder With Slack Adjuster
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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
Handbook on Maintenance of BMBC for ICF/RCF Page 30 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 31 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 32 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 33 of 41
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.
Handbook on Maintenance of BMBC for ICF/RCF Page 34 of 41
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.
Close cock 2 and open cock 3.
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
Handbook on Maintenance of BMBC for ICF/RCF Page 35 of 41
Test no.3 - layout for brake cylinder with built in slack adjuster
C. Take-up Length (without Quick Resetting Gear)
Close cock 2 and open cock 3.
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 cock 1 and open cock 2.
Close all cocks when the system is at atmospheric pressure.
D. Take-up Length (With Quick Resetting Gear)
Close cock 2 and open cock 3.
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
Handbook on Maintenance of BMBC for ICF/RCF Page 36 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 37 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 38 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 39 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 40 of 41
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
Handbook on Maintenance of BMBC for ICF/RCF Page 41 of 41
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