DO’s AND DON’Ts FOR RAIL SEAT ASSEMBLY ON CONCRETE SLEEPERS WITH ELASTIC RAIL CLIPS
Ensure that all components of the assembly are available. Check drawing number of components as stamped on them (expect on clip).
Ensure that sleepers are laid centrally and square to the centre line of the track.
Ensure that there is equal gap between rail feet and insert on both sides. Slew the sleeper laterally to achieve this.
Ensure that rail flange top is clean.
Ensure that liners are seated evenly on the rail.
Keep “toe” of elastic rail clip on the liner and fix if by using driving tool of approved design.
Ensure that the end face of central log of driven clips is flush with the face of the insert.
Do not assemble fittings unless complete set of fittings of correct/ matching drawing are available.
Do not fit liner upside down.
Do not liner till equal gap is available on either side if rail foot.
Do not hit liner at top for seating evenly on rail.
Do not hammer the clip fixing.
Do not allow the central leg driven clip to either remain inside or project out of the eye of the insert.
CHECK–LIST FOR RESURFACING OF WORNOUT MEDIUM MANGANESE/90 UTS SWITCHES, CROSSINGS, SEJs AND CMS CROSSINGS
The following checks should be carried out during resurfacing:
Crossing condition: The crossing shall be inspected and it shall be ensured that it is reparable. In case, crack extends across the complete section either through nose or through wing rails, it should not be taken up for repairs. Bolt holes, if elongated, shall be re-deposited by welding followed by drilling.
Grinding: In case of single electrode system, it shall be ensured that after grinding, the depth of worn-out area is not less than 3 mm at any location.
Only those electrodes which are approved by RDSO shall be used (see list at Annexure –I, showing various brands of electrodes approved by RDSO).
Electrodes should be connected to correct polarity using recommended current. Tong testers will have to be used to determine actual current flow.
During welding, straight –edge should be employed continuously for correct build-up. After completion of welding, built –up area should be carefully examined and any under welded spot are deposited again while the crossing still remains hot.
Pre-heating of MM/90 UTS switches, crossings and SEJS before welding to a temperature of about 250 degree centigrade to 300 degree centigrade shall be done by to and fro movement of the oxyacetylene torch. The blow pipe shall not be held at one spot. No preheating is required for CMS crossings.
Welding shall be commenced immediately after pre-heating is discontinued.
Preheating of electrodes shall be done at 130 to 170 degree centigrade for at least one hour immediately before use. In case, the packing of electrodes is absolutely intact and all the electrodes are consumed within six hours after opening of the packing, preheating of electrodes may be dispensed with.
Complete removal of slag shall be ensured during welding with the help of hardened chipping hammer having flat and pointed ends and hardened wire brush having three rows of bristles on a width of 25 mm.
Electrodes with damaged and cracked coating shall not be used.
In case the crack in switch, crossing or SEJ is deep, instead of grinding, suitable cutting of gouging electrodes shall be utilised to remove such cracks easily.
Temperature of the switches, crossings and SEJs shall be checked during welding. It shall not exceed 300 degree centigrade for MMS/90 UTS switches, crossings & SEJs and 150 degree centigrade for CMS crossings.
In case of CMS crossings, it shall be ensured that the crossing is submerged in a water tank with only the head portion projecting out of water by 1 cm. Lower current of the recommended range shall be employed with stringer bead of shorter length, say 7 cm, deposited at a time. In case of CMS crossings, electrodes should be connected to positive polarity to reduce heat input.
It shall be ensured that all records regarding history of the switches, crossings and SEJs like number of times reconditioned, worn-out area reclaimed, electrode used, laying particulars, service life in terms of GMT etc. are recorded in a card or register. Preferably, card shall be maintained separately for each switch, crossing and SEJ (see proforma at Annexure-II for recording performance of reconditioned crossing).
For further details, the Manual for reconditioning of worn-out points and crossings, SEJs and CMS crossing shall be referred to. This Manual is presently under consideration of the Railway Board for approval and the same is expected to be issued shortly for implementation.