BOGIES AND SUSPENSION - South Central Railway

CHAPTER 6 – BOGIES AND SUSPENSION
WAGON MAINTENANCE MANUAL
Page 38 of 121
It has the same construction as that of bottom side-bearers except that
its flanges are inclined instead of being parallel to its bottom surface. The
inclination has been given to match the profile of the underframe to which it is
fitted.
The prescribed clearances for the side-bearers are as under:
Clearance in one side Total Clearance
New 3 mm Nominal 6 mm
Worn 6 mm Maximum 12 mm
As wagon body does not always rest horizontally, side-bearer
clearances should be measured on both the sides by feeler gauge. Action
should be taken on the basis of total clearance.
f) SPRING NEST ASSEMBLY
Spring nest assembly consists of two spring plates, four outer and four
inner coil springs. The bottom spring plate rests on the spring plank. The
nibbed portion of spring plate sits in the two holes provided in the spring
plank. This arrangement keeps the spring plate in position. There are four
washers riveted to each spring plate at suitable locations. At each of these
locations, one inner and one outer coil spring is placed. The raised portion of
the spring plank (made by riveting the washer) prevents displacement of the
coil springs. The inner coil has opposite hand to the outer coil. On the top of
these coil springs, the top spring plate rests. On the top surface of the top
spring plate, the floating bolster is placed. In the floating bolster, there are two
holes at each end to receive the nibbed portion of the top spring plate.
g) SPRING PLATE
It is made out of steel plate. On the outer side, it is bent at right angles.
There are four holes at a suitable distance to rivet washers with it. Washer is
made of steel. In the central position, the plate is nibbed at two locations. The
nibbed portion sits against the holes in the spring plate/floating bolster and
prevents the displacement of coil spring in service.
Generally four nests of springs are required on each side of the
bogie/trolley. The number may vary with heavier axle load bogies. The same
type of springs are used in the diamond frame and cast steel bogies. Each nest
consists of an outer coil spring and an inner coil spring of circular section. The
outer spring has left-handed coils while the inner one has right-handed coils.
These springs are made of spring steel hardened and tempered. After
manufacturing, the “IRS” part no., Maker’s name and year of manufacture
should be stamped as specified in the standard drawing while the spring is hot.