BOGIES AND SUSPENSION - South Central Railway

CHAPTER 6 – BOGIES AND SUSPENSION
WAGON MAINTENANCE MANUAL
Page 87 of 121
The axle has its lowest diameter at the journal. The dia of the journal,
therefore, is the limiting factor for deciding the gross load at rail.
The permissible gross load for standard and non-standard BG & MG axles has
been given in IRCA Part III Rule 2.8.10. Upto a certain reduced diameter of the
journal compared to the new, the axle cap carry full designed load, thereafter less than
the designed load. If full axle load has to borne at the reduced diameter of journal
should be condemned and re-axling of the wheels should be done. The axle can,
however, be used further by corresponding reduction in gross load and carrying
capacity of the wagon. However, this practice is not desirable from commercial point
of view. Axle should be changed as soon as its journal dia reaches the condemning
limit corresponding to the designed axle load of the wagon.
The distance between the centres of the 2 journals is also very important. The
spring shackle assembly axle box and axle guard for a particular type of wagon, have
a fixed journal centre. The correct distance between the journals as well as the
distance of individual journals from the outer surface of the wheel centre is, therefore,
very important and should be ensured. Its absence will cause difficulty in ensuring
correct alignment and the bearing brass will have a tendency to ride over collar on
one side and shoulder on the other side of the journal.
Many times the axle gets out on the shoulder portion by the back plate of the
axle box. Such an axle can be used again after turning the cut provided the cut is only
in the part where the dust shield may does not reduce the dia by more than 12 mm,
compared to a new shoulder dia and the width of cut is not more than 15 mm. The
portion which is turned, shall extend only upto that part of the axle upon which the
dust shield may bear. The radius should be provided as shown in IRCA Conference
Rule part III and the radius should be merged.
The axle also gets notched in service due to rubbing loose with loose brake
rigging parts or any other part. Thus effective diameter reduces and the axle may
break in service. Axle should looked for such defects at every stage and any axle
found with these defects should be withdrawn and replace.
The journal surface is a highly polished, which has to be handled with care in
workshop and other places. Sling chain or hooks, etc., therefore, should never be
applied to the journals for handling and lifting the wheels in workshops, sick lines and
other places,
Holes provided in the wheel centres may be used for this purpose. While
using the wheel it should be checked again for any mechanical damage likely to have
taken place during transportation and handling.
During service, many bearings run hot causing considerable damage and
scoring of journals. Such scored journal should be used only after proper grinding,
burnishing and testing. Wheels with scored journals should be sent to shops or to
depots, where facilities to do proper repairs exist. Such journals should not be used
on passenger service. Every time the axle runs hot a 5 mm size star mark should be
stamped on the face of the affected journal to distinguish it from other journal and to
know how many times the journal, in question, has run hot.