2. OBJECTIVES
• Safe coupling of Rail cars for optimum utilization as
per design
• Prevention of detention while Attaching Locomotive
with passenger rake.
• Avoidance of En-route CBC uncoupling or Train
parting.
• Addressing Common problems faced in LHB rake
CBC coupling.
3. WHAT ARE COUPLINGS
• Couplings are a group of mechanical devices used to
interconnect rolling stock.
• Couplings should be able to deal with different types of forces
(buff/draft) and compensate for variation in terrain and weather
condition.
• Couplings need to have a standard and compatibility to facilitate
long range rail freight and mail express transportation.
4. A BRIEF HISTORY
• Basic Chain and buffer: It
was the Standard in British
traditional railroads along
with Link and Pin coupling
• The maximum load carrying
capacity was very less which
pressed for a much needed
upgrade
5. • JANNEY COUPLING- It radically transformed railcar couplings.
• Also known as Knuckle, Buckeye, Tightlock, AAR(Association of
American Railroads) or Alliance coupling.
• It Facilitated automation, prevented accidents(crushing of workers
between cars), increased tonnage.
• Due to Superior Compatibility and standardisation (Safety Appliance
Act) it was an instant success.
• Patented in 1873, to this date Janney coupling is used in several
modified forms in IR and International railways
Pin drops in
locking position
6. TYPES OF COUPLINGS IN IR
• IRS Screw Coupling (WA/BD-125)- working load 22.5T.
• Enhanced Screw coupling (SK 99001)- working load 75T.
7. • Slackless Draw bar: 5 continuous BLC (Bogie Low platform
Container) wagon with end coupling as AAR CBC
• Automatic Buffing Contact (ABC) coupling- Used in all Meter
Gauge stock
TYPES OF COUPLINGS IN IR
8. • CBC couplings- A group of automatic couplings which use
Knuckle operation similar to the original Janney coupling.
• Schaku coupling- Developed by a German company, this
semipermanent coupler is widely used in DEMU/EMU
TYPES OF COUPLINGS IN IR
9. CBC
• A Centre Buffer Coupler is a mechanical device which connects
two rolling stock together to form a train and transmit draft and
buffing forces
• Indian Railways use AAR type CBC whose draft capacity is based
on the strength of Knuckle.
10. CENTRE BUFFER COUPLER
• CBC allows independent movement of rolling stock.
• It is centrally located at both ends and can transmit
Draft and Buff forces together.
• It can also accommodate track curvature and
elevation changes while remaining coupled together.
• Coupling action is automatic.
Draft force Buff force
12. • Transition coupling: Better known as ‘Dual Coupling’. It
incorporates a knuckle coupling alongwith a screw coupling.
• Screw Coupling is a modified form of Link/pin or chain coupling. A
M/exp standard for a long time, alongwith a pair of buffers.
• However It does not prevent climbing of coaches in Collision and
derailment.
• It has a very limited load carrying capacity(75T for enhanced screw
coupling) making it unsuitable for long range freight trains.
14. DIFFERENCE BETWEEN E
AND H TYPE CBC
• The Major Difference between E
and H type coupling is the Design
of Coupler head, wherein H type
CBC has an anti climbing feature.
• H type CBC also has a spring
loaded supporting device,
accommodating vertical jerks .
• Vertical restrictors are being used
when H type Rake is coupled with E
type Loco to provide Anti Climbing
feature.
15. MAIN ASSEMBLIES OF H TYPE
CBC
- Coupler head with
Shank
- Supporting device
- Draft gear
- Manual uncoupling
device
- Striker casting and Wear
Plates
- Knuckle assembly
- Lock lifter assembly
16. COUPLER HEAD WITH SHANK
H Type CBC head consists of a tightlock mechanism. Assume that you are
facing the knuckle.
When two stocks are being coupled, the left side “C” shaped lock pocket
slides over the tapered arm lock on the right side
This creates a Coupling which prevents vertical climbing in case of
derailment/ accident.
17. Supporting Device
• It consists of 4 preloaded compression springs.
• The coupler head rests on the top wear plate
• As the Coupler head is in “Tightlock” condition this
assembly absorbs vertical vibrations on run.
19. Manual Uncoupling Device
• It is also known as operating handle.
• It is mounted on one side of the rolling stock and connected
with the uncoupling mechanism through sliding rod.
• Handle is unlocked, lifted and rotated clockwise for uncoupling.
• A bolt type locking arrangement is made to prevent unauthorized
or accidental uncoupling
20. Striker Casting and Wear Plates
• Striker casting “houses” the CBC.
• It allows for a Vertical deflection of ± 7
deg and horizontal Deflection of ± 17
deg
• Base plate and support plates are fastened
to the under frame.
• A central pin is inserted to allow
horizontal deflection of CBC Head
Yoke pin support plate
21. Knuckle Assembly
• Knuckle Engages with the CBC
of other Rolling stock to
“couple” them together.
• It consists of a knuckle and a
lock Pin.
• It is fitted with the coupler
head and should NOT BE
REPAIRED. Always replace
with a new one if it is out of
gauge limits.
Knuckle thrower
22. Lock Lifter Mechanism
• It consists of a lock, toggle, a lever
connector and a Hook
• It also has a dropping lock and a Knuckle
thrower to push the knuckle out while
uncoupling.
• It is operated by means of a manual
uncoupling device also known as
operating handle
23. Tools and Gauges
• Knuckle Nose wear and stretch limit gauge.
• Inspects worn out knuckles and its vertical
stretch
• Knuckle must always be replaced in case of
gauge disqualification
Must touch knuckle body
Must NOT touch knuckle body
25. VERTICAL HEIGHT ALIGNING GAUGE
• It is used to inspect for
excessive distortion of vertical
aligning wing and/or gaurd arm
of the coupler head.
• It comes in two Variation i.e a
GO and NO-GO gauge.
NO GO GAUGE
26. CBC Coupling Procedure
Loco pilot shall supervise the coupling between CBC fitted rake and
Locomotive
being done by TXR staff at station and do coupling himself in mid section if
uncoupling take place.
1. After berthing of the rake at platform or after rake is made stationery
the five coach from first coach (inclusive SLR) hand brake to be applied.
2. The two skids shall be provided under the wheels of the SLR.
3. Loco shall be brought to the same line and stopped at 20 metres before
from the SLR.
4. The operating handle securing key of the SLR/First coach towards
engine to be unlocked.
5. CBC of the SLR/First Coach and CBC of loco shall be aligned in both
the knuckles i.e. of the locomotive and of the SLR/First Coach to be
kept wide open and bring in gathering range ie ± 110mm Horizontal and
± 90 mm vertical
6. Bring the vehicles closer with 2-3 Kmph speed and stop at about 1 meter
distance.
28. 7. Loco shall be moved cautiously at speed of 2 or 3 Kmph observing hand signals of
TXR staff at station or guard in mid section.
8. After coupling is made, it shall be checked the tell-tale slot of CBC of SLR/First
Coach and locomotive whether it is clear. As shown in the figure below .
9. It shall be checked by loco pilot to take notch to test coupling under observation of
hand signal of shunting supervisor at station or guard in mid section.
10. It shall be ensured to release the hand brake of coaches applied for coupling and get
removed the skids.
11. Whenever loco is to be used in screw coupling mode, it must be kept in mind that the
screw coupling must be in horizontal position at the time of knuckle locking with
clevis. Once coupling is ensured. It shall be ensured or provided that 50 mrn dia clevis
pin of loco is provided and tied with GI wire. It shall also be ensuredlprovided as per
the case washer and split pin in the clevis after being driven home.
CBC Coupling Procedure
NOTE: This procedure is
strictly Valid when the Coupler
axes are aligned
29. CBC alignment to be adjusted to
bring in gathering range
± 110mm Horizontal and ± 90
mm vertical
Horn and nose of coupling must
be set in a straight line .
Editor's Notes
As per RDSO Intruction Bulletin no MP.IB.LD.01.17.10(rev.00) dated 07.04.2010
