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INTRODUCTION The Axle Mounted Disc Brake System has been provided in LHB design Mainline Passenger Stock for Indian Railways. The brake system equipment provided on the LHB design coaches meet the requirement for high-speed trains hauled by locomotives and permits the emergency braking for such trains to be within the stipulated limits when brakes are applied on a straight trac at a speed of 160 kmph with loco brakes. DESIGN The axle mounted brake disc consists of a friction ring and a hub that are connected together and secured in place by nine screw connections. FUNCTION The brake caliper closes when the brake cylinder is actuated with compressed air. The brake pads come into contact with the brake disc, the braking effect begins. The axle-mounted brake disc which rotates with the wheelset axle is braked according to the pad SPECIFICATION: Dimension - 640 mm x 110 mm; Brake Radius 247 mm Type - Axle shaft mounted concentrically split, Material - Grey cast iron Friction ring wear (allowed) = 7 mm max. Weight = 126 kg . ABOUT BRAKE DISC: Internally vented axle mounted brake disc Good heat dissipation and high braking performance No maintenance required Wear checks/limits: No hair, incipient crack or through cracks permitted on Hub/connected flange: Incipient cracks on Disc: <72.5 mm, apart by 50 mm min. permitted propagating between two edges. <70 mm, apart by 50 mm min permitted propagating from the edges. Scoring upto 1mm allowed. Concave wear up to 2 mm allowed. Residual thickness up to 14 mm of disc friction surface. Slanting wear up to 2mm allowed. Permitted for breakage of 4 fins max. alternatively. Construction of the brake disc The below two picture depicts the cross section of the brake disc for better understanding.

Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

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Page 1: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

INTRODUCTION

The Axle Mounted Disc Brake System has been provided in LHB design

Mainline Passenger Stock for Indian Railways.

The brake system equipment provided on the LHB design coaches meet the

requirement for high-speed trains hauled by locomotives and permits the

emergency braking for such trains to be within the stipulated limits when

brakes are applied on a straight trac at a speed of 160 kmph with loco brakes.

DESIGN

The axle mounted brake disc consists of a friction ring and a hub that

are connected together and secured in place by nine screw connections.

FUNCTION

The brake caliper closes when the brake cylinder is actuated with

compressed air. The brake pads come into contact with the brake

disc, the braking effect begins.

The axle-mounted brake disc which rotates with the wheelset axle

is braked according to the pad

SPECIFICATION:

Dimension - 640 mm x 110 mm;

Brake Radius 247 mm

Type - Axle shaft mounted

concentrically split,

Material - Grey cast iron

Friction ring

wear (allowed) = 7 mm max.

Weight = 126 kg

.

ABOUT BRAKE DISC:

Internally vented axle mounted brake disc

Good heat dissipation and high braking performance

No maintenance required

Wear checks/limits:

No hair, incipient crack or through cracks permitted on

Hub/connected flange:

Incipient cracks on Disc:

<72.5 mm, apart by 50 mm min. permitted propagating

between two edges.

<70 mm, apart by 50 mm min permitted propagating

from the edges.

Scoring upto 1mm allowed.

Concave wear up to 2 mm allowed.

Residual thickness up to 14 mm of disc friction surface.

Slanting wear up to 2mm allowed.

Permitted for breakage of 4 fins max. alternatively.

Construction of the brake disc The below two picture depicts the cross section of the brake disc for

better understanding.

Page 2: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

Checking procedure

Safety and operational safety regulations

The axle-mounted brake disc has been built according to the state of-

the-art and recognized safety regulations. Nevertheless during its use it

may constitute a risk to the health and life of the user or third parties

and/or damage the device and other physical resources. The axle-mounted brake disc may only be used in a technically perfect

condition and for its intended purpose, paying attention to safety, risks

and the operating manual In addition to this instruction, you must observe and apply the binding

general statutory and other regulations on accident prevention and

environmental protection. The personnel commissioned to work with the axle-mounted brake disc

must read the maintenance instructions and particularly chapter with

safety instructions before starting work. Use personal safety equipment. Ensure that brakes (Service or Parking) are off before any operation

and the vehicle is over the pit for ease of checking.

Traceability

Before taking up any checking activity, ensure that the following

traceability data are collected and noted.

1. Zonal railway

2. Coach no.

3. Coach type

4. Commissioning date

5. POH date

6. Wheel Sl.no. (if visible)

7. Axe Sl.no. (if visible)

8. Axle position no. (Starting from Non Power Pack end)

Page 3: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

9. Disc position - LHS (or) RHS of axle (LHS on Non Power Pack

side)

10. Disc Serial no. (if visible)

11. Photos of the Disc in case of abnormalities found

12. Caliper + Actuator assembly - FT/KB

13. Checked by

14. Any other observations

To be used Tools

Calibrated Torque wrench (20 - 100 Nm range)

Socket for M12 nut (suitable for use in torque wrench)

Torch Light for better visibility

Hand held mirror (for clear view of disc closer to wheel)

Wiping cloth

Steel brush (to be profiled suitable for better accessibility)

Orientation of fixing numbers

Page 4: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

Cracks in Lugs of friction pair

Clean all sides of lug area (both nut and bolt head sides)

thoroughly to remove dirt particles.

Visual check for cracks / incipient cracks of lugs of the friction ring on

both sides of the disc (nut and bolt head side)

Note: If cracks are detected in any of the lug, the disc has to be taken

out of service immediately

Page 5: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

Check for Wheel shelling (deep pit / shelling marks)

Visually check for any pitting marks all around the wheel tread.

In case deep pit / shelling marks are found, make a note of the same and inform to

Shed authorities to replace the axles.

Check for Tightening torque

To be carried out only if there is a visible loosening of nut is observed.

If any such cases are witnessed, the below mentioned procedure is to

be followed.

Warning: Brake disc must have cooled down. Risk of injury from

burns when touching the hot brake disc.

> If parts are missing, replace parts according to part list.

> Maximum two non — complete fixings permitted. If more

detected the disc must be replaced.

> Set torque wrench at 50Nm.

> Tighten M12 nuts using torque wrench (diagonally

opposite).

> Stop when you hear the "Click" sound. Do not over

tighten anymore.

Page 6: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

> Make torque marking (on each nut, washer and segment).

Ensure that the torque mark color is different from the

existing one.

Part list fixing parts:

Part name Part no.

Segment D 128332-400

Bolt D 128599-200

Lock nut D 001754-101

Spring washer D 002651-101

TYPE OF DEFECTS

Penetrating crack, one-sided

Penetrating crack, both sides

Incipient cracks

Surface cracks

Scoring

Hollow wear

Splintering

Hot spots

Definition of Cracks

Type of Crack Defintion Figure Penetrating

cracks

Penetrating cracks are

cracks (fractures) that

reach from the inner to the

outer diameter of a

frictional ring side and

penetrate this over the

entire cross-section.

Type

of

Crack

Defintion Figure

Incipi

ent

crack

s

Incipient cracks are cracks in the frictional

surface that begin at the inner

or outer diameter of the friction ring and

penetrate the friction ring

side locally.

Surfa

ce

crack

s

Surface cracks are cracks in the frictional

surface that do not penetrate

the friction ring side in an axial direction.

Checking Parameters

S No Determining the

actual condition

Evaluation/measures

1 Wear marks on

friction ring.

The wear marks must be visible .Pay

attention to hollow wear & scoring

2 Hollow wear and

scoring in the

frictional surfaces.

The permissible values for the hollow wear

are 1.0

mm and for the depth of scoring 1.0 mm.

3 Splintering in the

frictional surfaces.

Unacceptable; replace friction ring.

4 Cracks.

4.1 Cracks in the

hub

Unacceptable; replace axle-mounted brake

disc.

Page 7: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

4.2 Cracks in the

connection &

screw

connection areas

of hub & friction

ring.

Unacceptable; replace axle-mounted brake

disc.

4.3 Cracks in the

frictional

surfaces.

Crack definitions

4.3.1 Penetrating

cracks.

Unacceptable; replace friction ring.

4.3.2 Incipient cracks. Unacceptable; replace friction ring.

4.3.3 Surface cracks. a) Permissible up to a length of 50 mm, when

the inner or outer edge is reached.

b) Permissible up to a length of half the friction

ring width if the gap to the inner or outer edge

is at least 10 mm. Surface cracks may not be

more than of 0.5 mm width.

4.4 Cracks in the

cooling fins.

Permissible on max. 2 cooling fins. Bet.

Cooling fins with permissible cracks there

must be at least 3 undamaged cooling fins

5 Foreign bodies

in cooling ducts.

Remove foreign bodies and clean cooling ducts

6 Hot spots Permissible.

7 Missing or loose

fastening, screws

and segments.

Unacceptable.

8 Loose friction

rings.

Unacceptable; check tight fit through visual

check

and shaking the friction ring. Tighten loose

friction ring.

Troubleshooting table The most common problems are listed in the following troubleshooting

table. Other combinations of faults are possible.

Fault Possible cause Remedy/measures

Development

of smoke

during

braking

(annoying

smell).

• Preservative not

removed before

commissioning.

• Frictional surfaces

dirtied by oil or the

like.

• None.

• Check the brake disc/pads;

determine the cause and

remedy

Air slot

between brake

disc

and brake pads

not parallel.

• Friction ring loose.

• Brake caliper stuck or

defective brake

cylinder

• Check: shake the friction

ring

• Check the fastening

elements, complete if

necessary. Tighten all

screws to the specified

tightening torque.

Scoring in the

frictional

surfaces

of the brake

disc.

• Foreign body or brake

disc abrasion has

gone into the brake

pad material.

• Non existence of

brake pads.

• Replace pads.

• Face friction rings if depth

of scoring unacceptable.

• Replace pads; check the pad

holder lock, replace the pad

holder if necessary.

Hot spots on

the frictional

surfaces of the

brake disc

(overheating).

• Pad material

unacceptable

• Unequal contact

pattern of brake pads.

• Driving with the brake

on.

• Overloading of

vehicle

• (axle load to high).

• unacceptable pressure

in

• brake cylinder.

• Check the pad type; fit

specified brake pads.

• Check hollow wear. Reduce

by overturning if necessary.

• Release the service and

spring applied brake. Check

brake control; repair if

necessary.

• Adjust the journey profile to

the permissible

specifications.

Page 8: Construction of the brake disc - Indian Railway · between brake disc and brake pads not parallel. •Friction ring loose. • Brake caliper stuck or defective brake cylinder •

Above-

average

cracking.

• Overload on brake

disc.

• Check whether the journey

profile or design parameters

are still correct for the brake

(e.g. higher weights,

deceleration, etc..); correct if

necessary.

• Check whether the damage

was caused by a blocking

brake cylinder or if the

vehicle was driven with the

parking brake on; remedy the

cause.

• Overload on disc brakes by

train driver (disuse of

brakes).

Uneven wear

on the two

frictional

surfaces of a

brake

disc.

• Blocking brake caliper

• or defective brake

cylinder.

• Unequal energy input

• in brake disc.

• Different grades of

pads.

• Check the brake caliper, repair

if necessary.

• Check the operability of the

brake cylinder, replace if

necessary.

• Check the brake gap with the

brake released.

• Check hollow wear. Before

installing new brake pads

remove any unacceptable

hollow wear.

• Fit the specified pad material.

Disclaimer:

It is clarified that this pamphlet does not supersede any existing provisions laid down

by RDSO, Railway Board or Zonal Railways. The pamphlet is for guidance only and it is not a

statutory document.

If you have any suggestion or comment, please write to:

Director (Mech), CAMTECH, Maharajpur,Gwalior (M.P.) – 474 005

Ph.0751-2470890, Fax 0751-2470841

(For Official Use Only)

PAMPHLET on

Instruction for Axle Mounted Brake

Disc in LHB Coach (FTIL Type)

Hkkjr ljdkj GOVERNMENT OF INDIA

jsy ea=ky; MINISTRY OF RAILWAYS

CAMTECH/M/GWL/2014-15/Beake Disc/1.0

Sept 2014

egkjktiqj, Xokfy;j & 474 005

Maharajpur, GWALIOR - 474 005