3. DESCRIPTION OF BOGIE
Introduction :-
Bogies works as a leg of locomotive.
It bears load of loco U/F, power pack , super structure
and other accessories of locomotive.
It is very important assembly as per loco running and
braking in concern.
Two bogies are used in one locomotive.
One bogie contain three axle, 6 wheel, 3 traction
motors, suspension arrangement. And brake rigging
etc. (except Bo-Bo bogie such as WDP1) .
.
4. TYPES OF TRUCK FRAME
A. According to wheel arrangement bogie are to
two type mainly.
* Bo-Bo Bogie ( Bi axle bogie, axle independently
driven ) it contain 2 axle 4 wheels, 2 TM.
* Co-Co Bogie ( Tri axle bogie, axle independently
driven ) it contain 3 axle 6 wheels, 3 TM.
B. According to truck frame manufacturing method.
* Cast steel type truck frame such as YDM4,
WDM2, WDS6, WDG4, WDP4.
* Fabricated truck frame such as WDG3A, WDM3D,
WDP2, WDP1
9. DESCRIPTION OF BOGIE
1. WDG3A/WDM3D loco is provided with fabricated bogie. This is a three-axle,two-stage
suspension with helical coil springs in primary stage and rubber
compression springs in secondary stage of suspension & floating type center
pivot arrangement.
2. The bogie frame shall be fabricated box type construction, manufactured from
steel plate to IS.2062 grade ‘C”.
3. The locomotive car body weight is transferred directly to the bogie frame
through four rubber “Compression” spring assemblies.
4. The bogie frame is supported through “soft primary” suspension consisting of
eight pairs of helical coil springs(inner & outer). Two springs mounted on each
equalizer, to provide ride quality and equalization of wheel-set loads.
11. DESCRIPTION OF BOGIE
continued
5. Center pivot does not take any vertical load and is used only for transfer
of traction and braking forces.
6. Four vertical hydraulic dampers are provided in primary stage between
axle and bogie frame.
7. Two hydraulic lateral dampers are provided in secondary stage between
bogie frame and the loco under frame.
Safety links are provided at the lateral stop locations between bogie
frame and the under frame.
9. These links serve to prevent separation of the bogie from the
locomotive car body in case of derailment and also provide means of
lifting the bogie along-with the locomotive car body.
12. DESCRIPTION OF BOGIE
continued
10. The Bogie is provided with conventional type, double
shoe per wheel powered by two air brake cylinders.
Manually operated slack adjusters are provided to
maintain the gap between brake shoe & wheel .
11. In WDG3A bogies, four numbers Bogie mounted sand
boxes provided for sanding during wheel slip.
12. Wheel arrangement is of Co-Co type.
16. Ride Characteristics
Designed speed 100 km/h for WDG3A
Designed speed 120 km/h for WDM3D
Axle load 20.5 t for WDG3A
Axle load 19.5 t for WDM3D
Wheel Diameter 1097 mm.
Condemning limit of wheel 1016 mm.
BHEL TM 4907 for WDG3A
BHEL TM 5002 for WDM3D
Gear ratio 18:74 (WDG3A)
Gear ratio 18:65 (WDM3D)
Curve negotiation – Minimum radius , which a loco
may negotiate – Here it is176 feet