Cleaning and greasing of Rocker & Roller bearings of open web through girders : In case of standard open web through girders, no separate jacking arrangement is required as the end cross girders are designed and provided with stiffener and pad plate for provision of jack for lifting. Gap between bottom of cross girder and top of bed block is about 600 mm, hence any type of jack of 100 ton to 200 ton capacity can easily be used for lifting. In case of non standard spans, the end cross girder requires adequate strengthening or special jacking beam below the bottom boom. The equipments required in this case are same as for sliding bearing except that the jacks of higher capacity (100 ton to 200 ton) and wire rope with turn buckle arrangement for holding the free end are required.
Greasing of rocker and roller bearing should be carried out under traffic block under the supervision of an official not below the rank of ADEN/ABE. Following precautions and preliminary arrangements are required:
1. Ensure tightness of rivets connecting end cross girder and end panel point of truss.
2. Provide hard wooden packing below the end cross girder to support the girder in case of failure of jacks. This should be done at three places to prevent tilting of this girder.
3. Remove fish plates and loosen dog spikes of rail over adjacent spans to avoid overloading the jack on account of weight of adjoining span and stiffness of the track.
4. If trolley refuge is connected to both spans on any pier, loosen the bolted connection of adjoining span to avoid overloading of jack and damage to the trolley refuge.
5. While lifting the fixed end, the other end being free, the girder is likely to creep longitudinally. To prevent this, provide hard wood packing
between the ends of girder on pier and between girder and the ballast wall on abutment.
6. Jacks should be kept in working order and tested to 1.5 times the load they are expected to lift. Keep one spare jack as stand by.
7. During lifting of girder, precaution should be taken to prevent creep of rail.