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Improved SEJ(laying, maintenance & inspection.). BY:- H arpal Singh (SSE/PWAY/RPJ). INTRODUCTION.
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Improved SEJ(laying, maintenance & inspection.) BY:- Harpal Singh (SSE/PWAY/RPJ)
INTRODUCTION On Indian Railways IRS design switch expansion joints were laid on both ends of LWR in lieu of Buffer rails. These SEJs are failing frequently as there were many cases of fracture of Stock rail/Tongue rail which is affecting Safety of running trains
DRAW BACK OF CONVENTIONAL SEJ • Stock rail fracture takes place at its reduction of section and due to involvement of bend. • Stock rail give up at about 20 – 40 mm away from the point of section reduction (throat) and 700 mm from its tail end which is left unsecured against longitudinal movement. The broken piece keeps moving away by hammering of playing wheels and discontinuity with wider gap in track especially in winter. • Hammering and breakage of bearing plates. • Chipping on throat of Stock rail & Tongue rail. • Level difference at throat of Tongue rail & Stock rail. • Spacing of sleepers at mid of SEJ 700 mm. • In case of fracture it is very difficult to carry out emergency repair. • Not suitable to for laying on curves sharper than 0.5 deg. • Rivets of MS flat which was provided to Stock rail are loosened and unusual sound heard while running of trains.
REQUIREMENTS OF IDEAL SEJ • To avoid bends in design of the Stock rail and Tongue rail. • To avoid any fractures in the bent portion of Stock rail & Tongue rail. • Suitable to lay on curves sharper than 0.5 deg. and up to 4.0 deg. • Suitability to higher axle loads. • Suitability for higher speeds. • In case of fracture part of Stock rail piece shall not move from its original position due to longitudinal forces.
TYPES OF IMPROVED SEJ SEJ with one gap Developed by M/s Rahee Industries Ltd, Calcutta. SEJ with two gaps Developed by M/s Bina Metalway, Jamshedpur. & M/s Chintuparni Engg. Works, Barabanki.
Advantages of IMPROVED SEJ Advantages of SEJ with one gap : • No bends in tongue and stock rail. • Only 5 sleepers of standard SEJ on PSC assembly are used. • Check rails guard against excessive play of worn out wheels. • Design suitable up to 200mm max. gap. Advantages of Two gap SEJ • The maximum gap is 57 mm which lead to lesser impact under passing wheels as compared to gap of 74 mm in IRS type. • It gives the field staff better control in providing correct nominal gap at the time of installation/ replacement of SEJ. • The minimum head width of tongue rail is more than 61% of full rail head width (44.75mm) as against 35% of head width (25.5mm) in conventional type. • The wear prone areas of heads of stock and tongue rails are pearlitised through a special process to achieve a hardness of 320 BHN • Maximum head thickness of stock rail is 89.5 mm as compared to 72 mm in IRS type of SEJ which in turn increases wheel support. • Status of stock rail is static as compared to moving type in IRS type of SEJ. • It is suitable to be laid in curves in steps of 1º,1.5º,2º,2.5º,3º,3.5º,4º by supplying pre curved stock rails. • The tongue rail being slender can be curved at site by the field staff.
Installation of Modified SEJ • Preparatory works. • Installation works. • Reference marks and gap measurements. • Routine maintenance of Modified SEJ. • Special maintenance. • Unusual occurrences. • Inspection and records.
Preparatory Works • Details plan of LWR track showing exact location of SEJ to be decided. • Distance between the ends of adjoining LWR between in which Modified SEJ to be laid shall be equal to length of Modified SEJ-2x13 m. • Material required as follows :- • Material required for one set of Modified SEJ as per drawing. • Sufficient number of 6.5 m long ultrasonically tested closure rails of same section. • Rail cutting equipment. • Sufficient number of 1 m fishplates with suitable clamps. • Equipment for protection work. • Sufficient manpower with tools.
Installation Works • Impose SR of 30 KMPH on the particular KM where SEJ to be inserted. • SEJ shall be pre-assembled as per drawing on PSC sleepers and kept ready beside of proposed location with suitable arrangement to shift on to track. • Minimum 1 hr. block to be obtained and both ends of rail shall be cut as per marking. • The existing PSC sleepers and rails to be removed. • Ballast shall be leveled. • Pre-assembled SEJ to be inserted in track & joined with suitable fish plate & clamps. • Ballast shall be recouped and track shall be attended to correct line and level. • Welding of both ends to be done as per availability of block. • SEJ gap to be adjusted as per LWR manual during distressing temperature.
Reference Mark and measurement • Pillars shall be erected at Centre of SEJ and reference marks shall be marked on these pillars on either side of track during distressing. • SEJ gap to be provided 40 mm. • Marking on pillars be shall be in form of saw marks. • A string shall be stretched across track over the saw marks of reference for measuring SEJ gap with respect to tip of Tongue rail/Edge of Stock rail.
Routine Maintenance & Special Maintenance • All fastening shall be complete and well secured. • Fastening shall be renewed on not more than one rail seal at a time. • Once in fortnight the SEJ shall be checked, packed and aligned if necessary. • Oiling and Greasing of Tongue rail & Stock rail shall be carried out once in fortnight. • During daily patrolling, the Key man shall keep special watch on the SEJ. • SEJ gap to be adjusted during distressing which shall be carried out as per provisions laid in LWR manual.
Unusual Occurrences • If another SEJ is not available for replacement, both damaged SEJ rail and undamaged SEJ rail on opposite side shall be replaced by closure rail and connected to LWR/SWR with suitable clamps and fishplates. • New SEJ to be installed.
Inspection & Records • Inspection shall be carried out on every fortnight during the two coldest and hottest months of the year during minimum and maximum temperatures at supervisory level and senior level. • Alternatively once in two months during other months at supervisory level. • Recording of inspection notes as per preformat given in LWR manual. • Compliance of observations of deficiencies is also entered in the inspection register.
