3 3 Different types of SEJ laying inspection

3. 3 Different types of SEJ laying, inspection & maintenance and lubrication. Periods- 1

Switch Expansion Joint • (1) An expansion joint installed at each end of LWR/CWR to permit expansion/contraction of the adjoining breathing lengths due to temperature variations. • (2) Normally, SEJ are provided for same rail sections. In case SEJ is required to be provided between the junction of two different rail sections such as 52 Kg rail and 60 Kg rail, Combination SEJ as per standard RSO drawing shall be provided. • Note: For the guidance of field officials, some of the commonly used Glued Joints and SEJ are as per Annexure 2/4 (A) & (B). For detailed information, respective RDSO drawings with their latest alterations and / or Track Manual may be referred.

Switch Expansion Joint • Location of SEJ: • The exact location of SEJ shall be fixed taking into account the location of various obligatory points such as level crossings, bridges, points and crossings, gradients, curves and insulated joints. • The various designs of SEJs in use on Indian Railways are as per Para 227 • (1) The conventional SEJ (RT-4160 and RT-4165) with straight tongue and stock shall not be located on curves sharper than 0. 5° (3500 m radius). • (2) The improved SEJs (RT-6902, RT-6914, RT-6922, RT-6930) may be located on curves up to 2°. SEJ beyond 2° and up to 4° shall be laid with approval of PCE in consultation with RDSO • (3) The SEJ shall not be located on transition of curves.

Commonly used SEJs

Different Types of SEJs

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.

Conventional sej

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.

COMPARISON BEETWEEN NORMAL SEJ AND MODIFIED SEJ S. No Features Normal SEJ Modified SEJ Merits 1 Bend in rails 1 in 8 No bend No breakage 2 Sleeper spacing at increases stability Mid of SEJ 700 mm 600 mm 3 Designed for 80 mm/120 mm 180 mm Less wheel Impact in large gap 4 Head thickness of Tongue rail 25. 5 mm 42 mm Increase life 5 Head thickness of Stock rail 72 mm 86 mm More wheel support 6 Status of Stock rail Unsecured Safety ensured 7 Suitability to lay on curves Limited up to 0. 5 deg. Can be laid up to 4. 0 deg. Scope for use 8 Provision of 1 in 20 can`t in SEJ sleeper Not provided Provided Built up twist avoided 9 Failure rate Very high For last five years no failure is reported Decreases maintenance cost

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-2 x 13 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.

About Standard SEJ • The IRS design of SEJ’s have been in service on IR since 1960’s. • The Stock rail and Tongue rail forming part of the SEJ have two sharp bends in close proximity. • In initial design of SEJ’s during 1960’s, 72 UTS Medium Manganese rails used.

Standard SEJ

Why Improvements is Required in Design ? • 1) To avoid two bends involved in the design of stock rail and tongue rail in conventional type of SEJ. • 2)To avoid fractures in the bent portion of stock rail and tongue rail in conventional type of SEJ. • 3)To meet other requirements like wide gap at bridge approaches.

Contd. . . • 4)Suitability in curves sharper than 0. 50 and up to 40. • 5) Suitability for higher axle loads. • 6) Suitability for high speed routes.

SEJs in vogue In case of LWRs laid on concrete sleepers having different rail section on either side of SEJs, combination SEJ to RDSO Drg. No T-6782 (52 kg / 60 Kg) shall be provided. Alternatively, two 3 rail panels (39 m), one of each rail section shall be provided with combination fish plated joint, between the two panels.

SEJ’s under trial • 1) SEJ with 60 Kg on curve with curvature > 20 and up to 40. • 2) SEJ for 80 mm gap with CR-120 crane rails

SEJ with one Gap • Design developed by M/s Rahee Industries, Calcutta. • Is also called as “Improved SEJ” • Comprises of a pair of two non bent rails mounted on C. I. Chairs with a expansion gap between the two juxtaposed rail ends. • A third rail (gap avoiding rail ) is securely bolted to the stock rail by HTS bolts to form an extension of the stock rail.

Contd. . . • The system also has check rails to reduce wheel hunting especially for worn out wheels. • Check rails also act as angle ties to keep the sleepers in position. • The wheel tread does not jump the gap but is smoothly guided in to the rail. • No risk of rail fracture or cracks –no bends or stress raisers. • All wheel transfer areas are head hardened to increase service life.

TYPES OF IMPROVED 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 200 mm 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. 75 mm) as against 35% of head width (25. 5 mm) 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, 2. 5º, 3. 5º, 4º by supplying pre curved stock rails. • The tongue rail being slender can be curved at site by the field staff.

Salient features of Improved SEJ • Excellent riding comfort. • Low life cycle cost. • No undue stress on the rails. • Capable of being laid on curved tracks. • Head hardened wheel transfer zone leading to longer service life • Smooth wheel transfer, increasing the life of rolling stock.

Contd. . . • Capable of handling gaps up to 200 mm and more with minor modifications. • Safe due to presence of check rails which guard against excessive play of worn out wheels. • Continuous support for wheel-set on rail ; no jump or change in level of wheel-set while negotiating gaps.

Contd…. . • The tongue rail is kept at mean position at center line of sleeper and stock rail end kept at 40 mm from mean position, thus creating a gap of 40 mm

Advantages of Improved SEJ (Rahee make) • No bends in tongue and stock rail. • Only 5 sleepers of standard SEJ on PSC assembly are used. • Check rail guard against excessive play on worn out wheels. • Design suitable up to 200 max gap. • Can be used on curve sharper than 0. 50 but not sharper than 1. 50

SEJ with Two Gap • Developed by M/s Bina Metal way Ltd, Jamshedpur & M/s Chintuparni Engineering works, Barabanki). • No bends in Stock & Tongue rails thus eliminating the safety risk. • Two gaps of 40 mm each between the tongue rail & stock rail. • Under temperature changes in track the gap in this SEJ would vary from 33 to 57 mm. • The smaller maximum gap of 57 mm as compared to 74 mm maximum gap in conventional SEJ reduces impacted caused at the joint when wheel negotiates the gap in the SEJ.

Contd. . • The minimum head width of tongue rail is more than 61% of the full rail head width as compare to 35% in conventional SEJs, due to this lesser wear & longer life. • Wear prone areas of heads of stock and tongue rails are pearlitized by a special process to achieve a hardness of 330 ± 20 BHN(Alt-1). • Stock rail is fabricated by machine and bolted together two separate rails. • Capable of being laid on curved tracks.

Contd. . . • The single rail C. I. chairs on sleeper nos 10 & 24 are designed to provide a toe load of 350 to 400 kg/clip to enable free rail movement.

Laying Details • SEJ makes use of 6 standard SEJ sleepers. 3 sleepers near each gap. i. e. Sleeper nos. 10, 11, 12, 23, and 24 • Length of SEJ is 5750+6950+5920+80=18700. • Sleeper n 0 -1 to 31 should be at a spacing of 600 mm c/c. • Mean position of SEJ should be kept at center line of sleepers no. 12 & 22. • The mean gap is 40 mm on each end

Contd. . • Stock rail is fabricated out of two pieces of lengths 7140 mm and 5920 connected to each other by HTS bolts.

Contd. . . • The tongue rails are kept at mean position at center line of sleeper nos. 12 & 22, and stock rail end kept at 40 mm from mean position, thus creating a gap of 40 mm • To arrest excessive creep in stock rail, stock should be box anchored.

Gaps at SEJ • (1) (a) The thermal force in a LWR as shown in Para 335 is to be resisted by suitable track structure. Accordingly, the Gap at SEJ depends on following factors: • (i) Longitudinal Ballast Resistance of sleepers (taken as 13. 28 or 13. 74 kg / cm / rail per sleeper for PSC sleeper of density 1540 or 1660 per km respectively, which is indicative and can vary as per site conditions) • (ii) Area of rail section • (iii) Modulus of Elasticity (E) for rail steel • (iv) Coefficient of linear expansion (α) for rail steel • (v) Difference between the De-stressing temperature and prevailing rail temperature of LWR • (vi) Initial gap at SEJ at de-stressing temperature.

(b) Gaps at SEJ

(b) Fig 3. 18 Setting of Gap at SEJ (IRS Design) to Drawing nos. RDSO/T-412, RDSO/T-4160, RDSO/T-4165, RDSO/T-5478, RDSO/T-5586, RDSO/T-5748, RDSO/T-6257, RDSO/T-6782 at De-stressing temperature (t d)

(b) Fig 3. 19 Setting of Gap at Improved SEJ with double gap of max. 65 mm each (DG 65 Design) to Drawing no. RDSO/T-6922 (60 Kg) & RDSO/T-6930 (52 Kg) (Applicable for both rails) at De-stressing temperature (t d)

(b) Fig 3. 20 Setting of Gap at Improved SEJ with Single gap of max. 80 mm (SG 80 Design) to Drawing no. RDSO/T-6902 (60 Kg) & RDSO/T-6914 (52 Kg) (Applicable for both rails) at De-stressing temperature (t d)

(b) Fig 3. 21 Illustration for measurement of gap at SEJ for observation of movement of LWR/CWR

Lubrication of SEJ by Keyman Periodical (fortnightly) oiling and greasing of SEJ, checking and retightening of fastenings at SEJ and other sleepers, if necessary. To watch for sun kinks, loose or missing fastening which may result in buckling or any damage to SEJ.