Wednesday, March 28, 2018

Systematic Overhauling

Systematic Overhauling –

(1) Sequence of operations-

Overhauling as described briefly should consist of the following operations in
sequence:–

(a) Shallow screening and making up of ballast.
(b) All items attended to, while doing through packing.
(c) Making up the cess.

(2) Shallow Screening and making up of Ballast–

(a) For good drainage periodical screening of ballast is essential.

(b) In the case of manual maintenance, the crib ballast between sleepers is opened out to depth of 50 to 75 mm. below the bottom of sleepers, sloping from the centre towards sleeper end. For machine maintained section, the crib ballast in theshoulders should be opened out to a depth of 75 to 100mm. below the bottom ofsleepers, sloping from the centre towards sleeper end. The ballast in the
shoulders opposite to the crib as well as the sleepers is removed to the full depth.
A slope is given at the bottom sloping away from the sleeper end. The ballast is then screened and put back. Care should be taken to see that the packing under the sleepers is not disturbed and the muck removed is not allowed to raise the cess above the correct level.
(c) Two contiguous spaces between sleepers should not be worked at the same time.

(d) Screening should be progressed in alternate panels of one rail length. In no circumstances should several rail lengths of track be stripped of ballast.

(e) Where drains across the track exist, they should be cleaned and filled with boulders or ballast to prevent packing from working out and forming slacks.

(f) After screening, full ballast section should be provided, extra ballast being run out previously for the purpose. Work should be commenced after making sure that the ballast will not be seriously deficient. Deficiency, if any, should be shown in the central portion of sleeper and this also should be made up soon.

(3) Through packing of track –

The detailed operations through packing may be done either by conventional beater packing, or by using machines.

(4) Making up of Cess –

Cess when high should be cut along with overhauling and when low should be made up. A template should be used for this purpose.
(5) General –

Overhauling should be completed before the end of March. In the case of L.W.R.
territory, the provisions in L.W.R. Manual should be followed.

(6) Screening in Welded area –

In the case of S.W.R. area screening may be carried out at rail temperatures and conditions.

Picking up Slacks –

Slacks usually occur on stretches of yielding formation on high banks and cuttings, on approaches of bridges, on badly aligned curves, where ballast is poor
in quality or quantity or where drainage is defective. Attention to slacks should be need based, need for the same being determined by inspections and results of track recording. Picking up slacks shall be done where the alignment is kinky or top level is uneven and the track has to be restored to normal condition quickly. The quantum of work turned out by a gang during the day will depend on the extent of slacks. In all cases sighting is done, the defects assessed and marks made on sleepers to be dealt with in chalk. The marked sleepers should then be dealt with as in through packing care being taken to see that the packing of adjacent sleepers does not get disturbed. In case a large percentage of sleepers need attention in a rail length, the entire rail length should be attended to. The marking of defects shall be as indicated below :

It is imperative that when joints are picked up, at least three sleepers on either side of the joints re packed. Picking up slacks may be done, by conventional method orby off-track tampers. In the case of a low joint, the fish plates should be slightly loosened and the joint tapped, so that the rail ends are, rendered free and are capable of being lifted. After the joint is thoroughly packed the fish plates should be tightened again.

Observance of Sleepers under passage of traffic -

During the passage of the first and last trains within working hours, the Mate and
gang men at the work site should stand on the cess each about one rail-length apart on either side of the portion of track they are attending to, whether through packing or picking up slacks and observe the movement of sleepers under load. Immediately after the passing of train, loose sleepers should be marked, packed uniformly and the packing tested. In respect of other trains, the Mate and the Gang Men should observe the sleepers near where they are working and take similar action. Firm and uniform packing is the primary need for good track maintenance.

Sample of standard section of track –

At or near the commencement of each gang length between stations a sample of three rail lengths of track should be maintained to accord with all standards laid down

(a) Formation of standard width and level below rail.
(b) Clean ballast of correct size, quantity and cross section.
(c) Correct alignment, level and gauge.
(d) Sleepers and fastenings in good condition.

The object of the sample track is to indicate the standard to which the track should be maintained throughout the gang length.

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