Measured Shovel Packing(MSP) of Joint Wooden Sleepers on Metal Sleeper Track

MSP of Joint Wooden Sleepers on Metal Sleeper Track

A joint is the weakest link in the track and special attention has to be paid towards its maintenance. The maintenance of joint sleepers is not very effective in the case of the conventional beater packing method because of the close spacing of the sleepers at the joint. The loosening of the packing at the joints results in a number of maintenance problems. MSP has been found to be very effective for packing joint wooden sleepers.

This method involves the usual through beater packing of the intermediate sleepers followed by MSP of the joint sleepers so as to bring the surface of the track to longitudinal and cross levels consistent with that of metal sleeper tracks. A detailed account of this procedure follows.

Calculation of total lift The total lift required is calculated by evaluating the voids at the joint sleepers and adding this value to the longitudinal lift required on account of the general sag of the track. The total lift for the two rails is then assessed as follows:

Total lift for sighting rail = longitudinal lift + voids under the sighting rail Total lift for second rail = fleximeter reading on sighting rail + voids under

the second rail + cross level difference at the joint

The cross levels are then correctly noted with the help of an accurate gauge-cum-level.

Lifting and packing of joint sleepers Joint sleepers are lifted to the required extent, but not more than 40 mm by means of non-infringing jacks. The required quantity of small stone chips are placed under the joint sleepers with the help of packing shovels. The jacks are then released from their positions and the sleepers are tamped with the help of blunt-ended crowbars so that they are evenly seated on the layer of chips.

Alignment corrections General alignment corrections are made while work is underway on the intermediate sleepers by way of the conventional beater packing method. Any disturbances that occur in the alignment during the MSP of joint sleepers are subsequently corrected.