This document provides information on rolling stock components and defects. It discusses wheels, suspension systems, and vehicle bodies. Specific wheel defects like thin flanges, worn roots, and flat tires are described. Suspension systems use springs, and defects in laminated and helical springs are covered. The document also discusses wheel-axle measurements and tolerances. Buffers and their defects that can cause eccentric buffing forces are explained. Finally, the document briefly introduces bogies and the four main types used for goods stock.

1. ROLLING STOCK

2. REFERENCES
• IRCA Conference Rules, pt.III for Goods stock
• IRCA Conference Rules, pt.IV for Coaching stock
• Schedule of Dimensions
• Maintenance Manual for BG Coaches, 1995
• Maintenance Manual for Wagons, 2001
• RDSO’s Manual of Instructions (MI) for Coaching Stock
– 105 kmph standard
– 110- kmph standard
– Rajdhani standard
• AC Traction Manual, Signal Manual etc
• Various respective Instructions, Manuals and Circulars

3. ROLLING STOCK
• There are three distinct portions of
rolling stock:
• Wheel sets
• Suspension system
• Vehicle body

4. WHEEL PROFILE

5. WORN WHEEL/WEAR ADAPTED PROFILE
• Rail interaction with IRS wheel profile results
in rapid wear of the flange and root of the
flange during initial stages till a wear
adapted/worn wheel profile is obtained
• Since the wear after the worn wheel profile
is obtained in service is considerably less,
wheels are now provided with worn
wheel/wear adapted profile

6. X=44mm
Y=28.5mm
ZR=14.5mm

7. WHEEL TYRE DEFECTS
NOTE-FOR SPEEDS MORE THAN 110 KMPH,
THIN FLANGE IS BELOW 22 MM
THIN FLANGE

8. EFFECT ON SAFETY (TYRE DEFECTS)
THIN FLANGE:
i) Oscillations increase due to greater play, greater lateral
force
ii) Angularity of the axle increases
iii) Besides, the back of the wheel may damage the tongue
rail while passing through the switch flange-way gap of
points and crossing

10. Sharp Flange

11. EFFECT ON SAFETY-
SHARP FLANGE:
i) µ increases
ii) Positive eccentricity increases even with
the same value of axle angularity
iii) May split open slightly gaping points
while traveling in facing direction, or may
mount over a slightly chipped tongue
rail.

12. WORN ROOT

13. EFFECT ON SAFETY-
WORN ROOT:
i) Positive eccentricity increases
even with the same value of axle
angularity
ii) µ increases (Change in surface
characteristics of flange slope)

15. EFFECT ON SAFETY-
DEEP FLANGE
• Deep flange coupled with vertical
wear of the rail head would tend
to ride on the fish plates and check
/ distance blocks-> not desirable

17. EFFECT ON SAFETY-
FALSE FLANGE / HOLLOW TYRE
(i) May split open points while
traveling in trailing direction
(ii) May get suddenly lifted and
dropped down near the nose of
the crossing while negotiating
the crossing.

21. WHEEL FLAT TYPRE
Permissible values as per RDSO’s letter
No.MC/WA/TP dated 28.12.92.
i) Goods Stock : 60mm
ii) Coaching Stock & Locos : 50mm

22. EFFECT ON SAFETY- FLAT TYRE
• Cause high dynamic augments on the rails.
Rail stresses may get increased by 2½
times particularly at
slow speeds of 20-25 kmph
• More awareness should be inculcated in
all the staff to observe flat tyre and report.

23. SHATTERED RIM
Wheel with a fracture on tread or flange->must be withdrawn from
service immediately.

24. SPREAD RIM
Due to internal material defect, it is not RIM FLOW which is a uniform
Curling over the outer edge of the RIM around the entire wheel

25. SHELLED TREAD
Pieces of TREAD breaking out of the tread surface in several places.

26. THERMAL CRACKS
Due to intense heating of the wheel arising out of severe break binding

27. HEAT CHECKS
Superficial, due to heating/cooling cycles during normal breaking

28. WHEEL GAUGE
• To be checked at Quarter Points
• COACHING /GOODS STOCK
1600 MM (1602-1599)
 No variation among the values of quarter points of
same axle is permitted,
 If variation-> a bent axle

29. A=1602
B=1599

30. TYPE OF BOGIE/
WAGON
On the
same axle
ON SAME BOGIE ON SAME
WAGON
4 WHEELED TROLLEY 0.5 mm 13 MM 25 MM
6 WHEELED TROLLEY 0.5 mm 6 MM 6 MM
4 WHEELED WAGON 0.5 mm - 25 MM
VARIATION OF WHEEL DIA ON THE SAME AXLE
<0.5 MM IN SHOP
Ref. 3.4.9

31. Wheel Tread Dia
• Difference of Dia on the same axle: persistent
angularity
• Excessive difference of dia on different axles of
the same vehicle-> adverse effect on buffer
heights

32. DIAMETERS OF WHEEL USED ON BG STOCK WITH
CONDEMNING LIMITS
SN Axle Load
(t)
Type Dia on
tread
when
new
(mm)
Condemning
tread dia (mm)
Wear
Allowance
(mm)
1 16.3 &
19.33
Solid 1090 990 50
2 “ Tyred 1090 1015 37.5
3 22.9 Solid 915 813 51
4 “ Tyred 915 813 51
5 20.3 Solid 1000 860 70
6 22.9 Solid 1000 906 37.5

33. SERVICE LIMITS FOR DIFFERENCE IN WHEEL DIA
IN LOCOS
DIAMETER
MEASURED
ON
TURNING
TOLERANCE
SERVICE
TOLERANCE
SAME WHEEL 0.5 MM 2.5 MM
SAME AXLE 2.0 MM 8.0 MM
SAME BOGIE 15 MM 25 MM

34. SUSPENSION SYSTEM
1. Springs: To negotiate track
twist and improve
riding comfort
i) Single Stage
Suspension:
Only one stage of
springs between
wheel set and vehicle
body
ii) Double stage
or two stage
suspension:
Provided in two stages

35. • Contd…
a) Primary
Stage:
Bear on the axle boxes directly /
indirectly called primary springs;
primary suspension
b) Secondary
Stage:
The set of springs bear directly the
weight of vehicle body (through the
bolster) and transmit it to a bogie
frame which further rests on
PRIMARY SPRINGS. Coaching stock
and Locos normally have two stage
suspension

38. LAMINATED SPRINGS
1. GRADING: Springs are divided in 4
groups according to variation in camber
w.r.t. nominal size viz; ‘A’, ‘B’, ‘C’ & ‘D’.
It should be ensured that, all four springs
of a wagon belong to the same group or
one group higher or lower.

39. DEFECTS IN LIMINATED SPRINGS
• FREE CAMBER: In general tolerances of measured
free camber from design camber are:
i) Loco & Carriage Springs-> –0 +3mm
ii) Goods Stock, BG-> -0 +6mm
• WORKING CAMBER: Measured on a level track in
loaded condition
– In case of a 4-wheeler wagon, difference in
working camber between any two springs shall
not exceed 13mm (Worse if the difference on
diagonally opposite springs)

40. Body weight – Side bearers – Bolster – secondary springs –Spring plank- Swing links –
Bogie frame – Primary springs – Roller bearing – Journal – Wheel
Helical Spring

41. LAMINATED Vs HELICAL SPRINGS
1. Laminated springs require periodical attention and
maintenance
2. Laminated springs provide excessive damping if
not maintained properly
3. Laminated springs’ action is erratic
4. Some laminated spring assemblies are ineffective
at high speed
5. Laminated springs required more raw material
6. Helical springs require use of dampers
7. Helical springs are of low weight

42. COMMON DEFECTS IN HELICAL SPRINGS
1. Cracked or broken
2. Shifted spring
3. Spring fully compressed
4. Loss of elasticity (fully compressed in
dynamic condition)
5. Tapped with a light hammer. A dull
sound would indicate the presence of
crack or flaw.

43. AIR SPRING
• Ideal for passenger carrying vehicles and is used
where there is a large payload ratio (pay load to
tare weight) and a requirement to tailor the
breaking effort to the vehicle mass
• Similar to a car tyre and is permanently connected
to an auxiliary surge reservoir by an
interconnecting pipe. The mass of air in the
system is controlled by means of a mechanical
levelling valve.
• In EMU trains of CR and WR

44. EMU

45. DAMPING
• FRICTION DAMPING; laminated
spring, also in BEML coaches
• HYDRAULIC DAMPING-ICF all coil,
locos

46. FRICTION DAMPING

47. Hydraulic Damping

48. Play of bearing at journal

49. • Min. & max. perm. Lateral play
between the bearing brass and the journal for
B.G. shall be:
Trolley 4 Wheeler
Min. 5mm 5mm
Max 10mm 10mm

50. AXLE GUARD HORN CHEEKS
to hold the axles in a rigid wheel-base
 while performing the above function, to
permit unhindered relative vertical movement
between the vehicle body and the axle, to
enable the springs to deflect and function
freely

51. AXLE GUARD HORN CHEEKS
• To have maximum life out of the axle guards, a
piece called horn cheek is rivetted to the axle
guard
• It rubs against the groove surfaces. On
wearing out, the horn cheek can be replaced
by a new one without the need of replacing
the entire axle guard.

52. Plan
Longitudinal Clearance Lateral Clearance
Clearances between horn cheek and axle box groove
movement

53. Clearances between horn cheek and
axle box groove
• Lateral clearances
• Goods, coaching stock & 4-w stock
Coaching
BOX CRT
Min
(shops/POH)
6 mm 20 mm 12 mm
Max
(maint.
Depot)
10 mm 25 mm 18 mm

54. Clearances between horn cheek and
axle box groove
• Longitudinal clearances
Coaching
stock
BOX
wagons
Min
(POH)
3 mm 12 mm
Max
(service)
10mm 18 mm

55. ROLLER BEARINGS
Type of Roller Used in
1 Cylindrical BEML coaches, some
engines some wagons viz
BOX, BCX, BRH etc.
2 Spherical (Dia at ends
is lesser than dia at
the centre).
ICF coaches, some
engines some wagons
viz. BOBS etc.
3 Tapered Some Engines, some
wagons viz. BOXN, BCN
etc.

56. Cylindrical Roller Bearings
• Cylindrical in shape
• Are provided in BOX, BCX and BRH
wagons

57. SPHERICAL ROLLER BEARINGS
(ICF all coil ,some engines & BOBS etc)
• Spherical roller bearings are also called self
aligning roller bearings. When either due to
curve or side oscillations the rollers get
displaced, the rollers automatically align
themselves to their central position
• The axle boxes can tilt up to 2°. The roller
bearings are so designed that they can get out
of alignment by 2 to 3mm without any
detriment to their performance.

58. TAPERED CATRIDGE
(Some Locos,BOXN, BCN )
• These bearings are designed to take both radial and
lateral loads.
• It consists of 2 rows of tapered roller bearings kept
apart by a spacer ring over the inner race
• During the run the outer race is held firm in the
adaptor and the inner race rotates along with the
axle and the roller bearings, rotating about the axis
of journal.
• In case of any defect, the outer ring starts rotating
under the adapter producing a loud whistling noise

59. PR Plates
• On the left hand side of each sole bar or on
the wagon body, PR plates are fitted or PR
particulars are stenciled
• P: Periodical overhaul of axle boxes
• R: Re-examination and greasing of axle boxes

60. BUFFING GEARS/BUFFERS
• Performs the basic function of absorbing
buffing impacts
• Buffer defects have significant effect on
derailment proneness
• The effect is due to eccentricity of buffing
forces
 The eccentricity of buffing forces may be in
vertical and/or horizontal direction

61. DEFECTS RESULTING IN VERTICAL ECCENTRICITY BUFFING
FORCES:
(i) DIFFERENCE IN HEIGHT OF BUFFERS.
Max. & Min. perm. Buffer heights BG (Goods &
Coaching)
Empty Loaded
1105mm 1030mm
Note: To make up the buffer heights to max.
permissible limits due to reduced dia of wheels, a
packing piece of required design and size may be
interposed between axle box crown and spring
buckle

62. Contd.
Defects in Buffer
(ii) Drooping buffer; Buffer displaced
vertically from its normal position due to
headstock being bent.
- On B.G. max. permitted displacement
of buffer face due to head stock bent is
35mm in any direction from its normal
position for wagons and 38mm for
coaches

64. .

65. DEFECTS RESULTING IN HORIZONTAL
ECCENTRICITY OF BUFFING FORCES:
i) Deficient buffer
ii) Dead buffer
• A buffer shall be considered dead when it is
ineffective or its projection from the headstock
(on BG) is below the prescribed min. limits
a) Goods stock
for long case: 584mm (max. 635mm)
for short case: 406mm (max. 456mm)
b) Coaching Stock: 584mm (max. 635mm)

66. DEFECTS RESULTING IN ECCENTRICITY OF
BUFFING FORCES IN BOTH DIRECTIONS
• Buffer face is displaced from its normal
position in an inclined direction, due to
headstock being bent.
• On B.G. maximum permitted displacement of
buffer face due to headstock being bent is 35
mm in any direction from its normal position
in case of wagons and 38 mm in case of
coaching stock

67. BUFFERING GEAR DEFECTS - REJECTION
1. GOODS STOCK
i) If any buffer deficient
ii) More than one dead buffer on two consecutive
wagons on a train
iii) More than three rivets missing from a buffer
plunger
iv) Buffer spindle broken or nut deficient or of incorrect
size

68. 2. COACHING STOCK:
i) Buffer deficient or drooping
ii) Any buffer dead
iii) Buffer spindle broken or nut
deficient

69. • CAUSES FOR LOW BUFFER HEIGHT
1. Overloading
2. Uneven loading
3. Weak or defective springs
4. Less dia of the wheel
5. Worn out axle brass

70. • IRREGULAR LOADING:
i) Difference of height from rail level of
more than 64mm between any two
buffers on the same vehicle measured at
the headstock.
ii) Flange of any wheel within 25mm of the
bottom of vehicle (under frame)

71. TWIST IN UNDERFRAME
1. LONGITUDINAL TWIST:
– By measuring the diagonals on a level track
– Will cause persistent angular running
2. VERTICAL TWIST:
– By measuring the height of sole bar at the
four corners of under frame on a level track
– Equivalent to a twist in the track

72. BOGIE ROTATION

73. BOGIE ROTATION
• A four-wheeler cannot be made too long
• The longer rigid wheel-base will not be able to negotiate
curves and turnouts
• Without developing excessively high flange forces and
excessive positive angularity
• When a longer vehicle body is needed to have a higher pay-
load, it is supported on two bogies, each of much shorter
wheel base

74. Hindrance against bogie rotation
• Incase of a derailment, body surfaces
taking loads be checked for any tendency
towards jamming
• The possible defects may be
Uneven wear in hemispherical pivot
excess wear in pivot
Lack of lubrication
Ingress of dirt

75. GOODS STOCK

76. BOGIES
8- WHEELER WAGONS, LOADS
TRANSMITTED THROUGH BOGIE TRUCK
(TROLLY) CONSISTS OF SIDE FRAMES,
BOLSER SUSPENSION COMPONENTS,
WHEELS, AXLES AND AXLE BOXES, BRAKE
GEAR ETC.

77. Goods Bogie
• FOUR TYPES:
1. IRS FOUR WHEELED CAST STEEL BOGIE
2. IRS FOUR WHEELED DIAMOND FRAME
BOGIE
3. FOUR WHEELED FABRICATED UIC TYPE
(BOX TYPE) BOGIE
4. FOUR WHEELED CAST STEEL BOGIE WITH
LONG TRAVEL SPRINGS AND SNUBBING
DEVICE (SNUBBER)

78. BOX WAGON
• FITTED WITH 4 WHEELED FABRICATED UIC TYPE (BOX
TYPE) BOGIE
• DESIGNED FOR 20.3 t AXLE LOAD
• WELDED, PLATE FABRICATED BOGIE HAVING FIXED
BOLSTER WITH HEMISPHERICAL CENTRE PIVOT AND
PRIMARY SUSPENSION INCORPORATING 4 LAMINATED
BEARING SPRINGS WITH LONG LINKS SUPPORTED BY
MILD STEEL STONES

79. BOX WAGON BOGIE

82. DEFECTS IN UIC TYPE BOGIE
1. WEAR ON CENTRE PIVOT ASSEMBLY :
• The two hemispherical surfaces have a
common radius of 200mm
• Due to wear these surfaces may no longer be
hemispherical
• To restore each to uniform hemispherical
shape each can be reduced in thickness by
3mm by machining
• Replace centre pivot if wear > 3mm

83. Contd…
2. SHACKLE PIN:
– The Diametrical clearance between shackle pin and spring eye
should not exceed 3mm
3. SHACKLE STONE: (Fig VI 9 wagon manual)
The Radii at the corners of the shackle and stone have been
increased from 6mm to 10mm to reduce stress concentration. In
no case, a stone with 6mm radius should be used in conjunction
with a shackle having 10mm radius
4. SHACKLE :
Shackles with 10mm radius painted yellow to
distinguish from shackles with 6mm radius

84. Contd…
5. SHACKLE SPRING :
SPECIAL FEATURES OF LAMINATED SPRING :-
i) Length between eye centres when straight= 1200 + 3
ii) Width of plate = 120  0.6
iii) Thickness of plate = 16 + 0.32
- 0.24
iv) Size of Eye = 36 + 1
- 0
v) Free camber = 47 + 6
- 0

85. Contd…
vi) Estimated camber under tare = 35
vii) Estimated camber under gross = - 4
viii) Deflection per tonne = 5.58
Max. permissible variation in the free camber of
any two spring is 12mm.

86. Contd…
6. HORN CHEEK :
Must be replaced if reduced to 13mm
in thickness i.e. worn-out by 4.5mm
or when total wear on axle box lug
and horn cheek reaches 5mm

87. Contd…
• 7.HORN GAP STIFFENER :(Fig VI 15 WM)
• Clearance between axle box & horn cheeks
< 18mm
• the short leg of horn cheek < 12mm thick.
• Special attention to be paid to lateral and
longitudinal clearances between axle box and
bogie frame as these clearance govern the
floating characteristics of the wheel set

88. Contd…
8. AXLE BOX LUGS :
Considering wear on axle boxes,
 Max. limit of total
Long. clearance 18 mm
 Max. limit of total
Lat. Clearance 24.5 mm

89. CASNUB BOGIE
• CAST STEEL FRINCTION SNUBBER BOGIE
• 1972-FITTED ON BOI (TESTED UPTO 110
KMPH)
• 1981-FITTED IN BOX – N (TESTED UPTO 90
KMPH)

90. CASNUB Contd…
VARIOUS BOGIE VERSIONS
1. CASNUB-22W
2. CASNUB-22W(Retrofitted)
3. CASNUB-22W(M)
4. CASNUB-22NL
5. CASNUB-22NLB
6. CASNUB-22HS( AT 100 Kmph)

91. i. Wheel set with Cartridge Bearing
ii. Axle Box/ adapter, retainer bolt & side frame key assembly
iii. Side frames with friction plates and brake wear plates
iv. Bolster with wear liners
v. Spring plank, fit bolts & rivets
vi. Load bearing springs and snubber springs
vi . Friction shoe wedges
viii. Centre pivot arrangement
ix. Side Bearers
x. Elastomeric Pad
CASNUB

92. CASNUB Contd..
Fig.No.3.69

93. CASNUB Contd..
Fig.No.3.70

94. CASNUB contd..

95. CASNUB contd…
1. Side Frame Column Sides 2. Anti – Rotation lugs
3. Side frame friction liners 4. Pedestal Crown Roof
5. Pedestal Crown Sides & Pedestal Sides 6. Pedestal Jaws
LOCATIONS OF WORN SIDE FRAME

96. CASNUB Contd…
Two cast side frames and a floating bolster
• Bolster supported on side frames through two groups
of springs which also incorporate load proportional
friction damping. Side frames connected by
fabricated mild steel spring plank
• Fitted in BOXN, BCN, BCNA, BRN, BTPN, BTPGLN
Wagons. Max. Population on BOX N Wagons
• Hunting at 90 kmph

97. CASNUB Contd…
• CASNUB BOGIE/BOX ‘N’ WAGON
• SUSPESION CHARACTERISTCS
1) The bogie suspension is at the bolster
level only.
2) As there is no primary suspension system,
the spring plank is subjected to bending
and torsion during the wheels trying to
adjust, for negotiating track twist

98. CASNUB Contd…
3) The cast steel-floating bolster is supported on
the side frame through two nests of springs.
4) The springs contain friction snubber for
oscillation control. However these snubber
springs are not designed to take vertical load of
the wagon
5) The positive features of these bogies are
lightweight, shorter overall length, ease of
maintenance, high reliability and higher
capacity of payload of 22.9t axle load

99. CASNUB Contd…
6) The salient features of this bogies are –
Wheel Diameter: 1000mm (new), 925mm
(condemning)
Wheel base: 2000mm
Type of pivot: IRS spherical
Type of roller
bearing:
Standard AAR tapered
cartridge bearing
Anti rotation
features:
Anti rotation lugs have
been provided between
bogie bolster and side-
frame

100. CASNUB Contd…
7) CASNUB 22-W (M) is an improvised
version of model CASNUB 22-W. In these
version elastomeric pads at the side
bearer level and at the axle box level have
been provided, this reduces hunting
proneness of the bogie and biased wear
of the wheel flanges.
8) The bogie is fitted with two groups of
helical springs nests the number of
springs in a group can vary for various
axle load is as under:

101. CASNUB Contd…
9.Axle
load
No. of springs
Outer Inner Snubber
22.9t: 14 10 4
20.3t: 12 8 4
16.3t: 8 8 4

102. CASNUB Contd…
NOTE: 1) Snubbing
arrangement & snubber
Springs are same for 22.9t,
20.3t & 16.21 Axle Load
2) Details of the springs are
as per Drg,No.WD-83069-
S/1
AXLE
LOAD
No. of springs required
Outer Inner Snubber
22.9t 7 5 2
20.3t 6 4 2
16.2t 4 4 2
DETAIL OF SNUBBING, SRING GROUP ARRANGEMENT CASNUB
BOGIES (EXCEPT CASNUB-22 HS BOGIE
16.2t axle load
20.3 t axle load
22.9 t axle load

103. CASNUB Contd…
10)Each bogie is provided with four
friction snubbers for the purpose of
damping of the oscillations. These
snubbers are in the form of
triangular cast steel, which is
supported at the snubber springs.
The springs should be replaced if
minimum spring height is at or less
than shown below:

104. Spring Free height
nominal
(mm)
Recommended
condemning
free height
(mm)
Outer load
spring
260 245
Inner load spring 262 247
Snubber spring 294 279
Matching of both load and snubber spring is
important. The springs should not have free
height variation more than 3mm, assembled in the
same group.

105. CASNUB Contd..
11) Body weight is transferred to the bogie
through IRS spherical centre pivot. Centre
pivot is to be lubricated with graphite
grease.
12) CASNUB 22-W bogie is provided with a
roller type side bearer, it has now been
modified to constant contact metal
bonded rubber pad
13) The main clearance of bogie assembly is
placed as under.

106. 14) Clearances of Bogie
Assembly
(Fig.8.23)
Cylindric
al roller
bearing
axle box
Cartridge
type unit
adapter
(1) Lateral clearance
between side frame
and bolster
18mm 18mm
(2) Lateral clearance
between side frame
and axle box adapter
25mm 25mm
(3) Longitudinal clearance
between side frame
and axle box adapter
2mm 2mm

107. CASNUB Contd…
(4) Clearances of Bogie
Assembly
Cylindric
al roller
bearing
axle box
Cartridg
e type
unit
adapter
(5) Longitudinal clearance
between side frame and
bolster
6mm 6mm
(6) Lateral clearance
between side frame and
axle box crown
7mm 7mm
(7) Clearance between Anti-
rotation lug and bolster
4mm 4mm

108. CASNUB Contd…
15)
CASNUB bogie assembly consists of side
frames, spring plank, bolster, friction shoes,
load bearing spring, snubber spring, centre
pivot, wheel set with roller bearings.

109. COACHING STOCK
• I R S
• I C F LAMINATED
• B E M L (BHARAT EARTH MOVERS LTD)
• I C F ALL COIL

110. Conceptual Top View

111. Conceptual Isometric View

113. IRS BG (Bogie)

114. ICF Laminated Bogie

115. BEML BOGIE

116. ICF all Coil Bogie

117. LOCO

118. WHEEL FLANGE PROFILE FOR DIESEL
AND ELECTRIC LOCOS – B.G.
WEAR ADAPTED PROFILE

119. WDM2

121. WDM 2
• Suspension Characteristics
• This diesel electric locomotive with Co-Co
bogies has been designed for mixed traffic
service with a rated horsepower of
2600/2400
• The transmission system consists of six axle
hung nose suspended traction motors, one
each axle.
• It has the centre Pivot and two side bearers

122. Contd.
• The pivot carries 60% of vertical load and
also transmits tractive and braking forces
• The two side bearers working in oil bath
carry the remaining 40% of vertical load
equally distributed
• It has a single stage suspension. The spring
system consist of 4 groups of 2 nests of
springs, each nests is helical coil spring

123. Contd.
• The spring nests are mounted on equalizing
beam, which is resting on axle box
• Damping is provided by four units of spring
loaded friction snubber providing damping
• Wheel diameter is 1092 mm
• Wheel base for bogie is 3810mm
• The snubber assembly consists of 3 alloy steel
friction shoes working up and down in a case
hardened sleeve

124. Contd.
• The shoes are pressed against the sleeve by
thee pre-compressed springs equally
spaced vertically and radially.
• A transverse play ranging from 3.175mm
minimum to 6.35mm maximum is available
between axle boxes and horn guides in case
of outer axles

125. Contd.
• Transverse play between the centre axle
boxes and the horn guides ranges from
12.7mm minimum to 15.8mm maximum.
The total longitudinal clearances in 1.59mm
in all cases, the maximum permissible are
4.76mm
• The suspension system has been designed
in such way that all axles carry equal load

126. Contd.
Defects
• The surfaces of centre pivot as well as of the two
side bearers should be checked to see if there is
any tendency for causing hindrance to bogie
rotation
• The condition of the spring loaded friction
snubber should be checked to see whether
damping is adequate or not
• The equalizing beams should swivel freely at their
points of support on the axle boxes, otherwise
off-loading of one wheel will not be shared by
the adjacent wheel or wheels.

127. WDM4

128. WDM2 (modified)
• Increased speed potential
• Resilient thrust unit at the axle boxes of each
bogie
• Extra free float (lateral freedom) to to middle
axle to negotiate sharper curves

129. WDM4
• Two stages of suspension, both at primary and
secondary levels
• Damping at secondary stage by two spring
loaded friction snubbers on each bogie, no
dampers at primary stage
• A resilient thrust unit at journal box assembly
to cushion the lateral impact

130. • THANKS
• Take pride in what you do
• Love what you do
• Believe in what you do