Technical specification for Improved SEJ, Provisional’ 2008
(Drg. No. RDSO/T-6902 to 6921)
Indian Railway Standard Specification for Improved SEJ of 80mm max. gap
(Serial No. T-60 – 2021)
1. All rails used for fabrication of Improved SEJ shall be ultrasonically tested, bend free,
heat-treated and stress relieved.
2. All the provisions contained in RDSO’s ISO procedures laid down in Document No.
QO-D-7.1-11 dated 19.07.2016 (titled “vendor-changes in approved status”) and
subsequent versions/amendments thereof, shall be binding and applicable on the
successful vendor/vendors in the contracts floated by Railways to maintain quality of
products supplied to Railways.
3. Rails: The rails used for manufacturing of Improved SEJ are normally supplied by
the Purchasing Railway. The rails received from the Railways shall be inspected
visually for surface defects like cracks, seams, laps, pipes, rusts and scales. The rail
shall be tested ultrasonically for detection of internal flaws before subjected to further
operation. The procedure for ultrasonic tests shall be as per standard method issued
by RDSO. The Gr.880 rails are susceptible to crack on application of heat and as
such flame cutting and drilling must be avoided. Guideline for handling and
maintenance of Gr.880 (90UTS) rails issued by RDSO should be followed.
4. Manufacturing Practices: All ultrasonically tested rails shall be carefully machined,
drilled or cut to dimensions as shown in relevant drawings. Rail used for manufacture
of Improved Switch Expansion Joints shall be Head hardened (Heat-treated).
1.1 5. Improved Switch Expansion Joints:
1.1.1 5.1 Stock rails for Improved SEJ:
The holes in the web of the stock rails shall be registered with reference to the base
of the rail and to the toe end of the rail within ±0.8mm. Diameter of all holes shall be
correct within ±0.8mm tolerance. The length of stock rail shall be correct within
±0.3mm tolerance. The planning correctness shall be within ±0.5mm when tested
with profile gauges. Stock Rail shall be head hardened min 1500mm from the toe
end. Hardness of head hardened portion shall be as specified in 1.1.6 Para 5.6.
1.1.2 5.2 Tongue rails for Improved SEJ:
The length of tongue rail shall be correct within ±3mm tolerance. The planning
correctness shall be within ±0.5mm when tested with profile gauges. Tongue Rail
shall be head hardened min 1500 mm from the toe end. Hardness of head hardened
portion shall be as specified in 1.1.6 Para 5.6.
1.1.3 5.3 Gap Avoiding rails for Improved SEJ:
The holes in the web of the gap avoiding rails shall be registered with reference to
the base of the rail and to the stock rail end of the rail within ±0.8mm. Diameter of all
holes shall be correct within ±0.8mm tolerance. The length of gap avoiding rail shall
be correct within ±1mm tolerance. The planning correctness shall be within ±0.5mm
when tested with profile gauges. Gap avoiding rail shall be head hardened
throughout its length. Hardness of head hardened portion shall be as specified in
1.1.6 Para 5.6.
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1.1.4 5.4 Check rails for Improved SEJ:
The holes in the web of the check rails shall be registered with reference to the base
of the within ±0.8mm. Diameter of all holes shall be correct within ±0.8mm tolerance.
The length of check rail shall be correct within ±5mm tolerance. The planning
correctness shall be within ±1mm when tested with gauges
1.1.5 5.5 The clearance between the mating surfaces of stock rail and gap avoid rail, tongue
rail and gap avoid rail shall not exceed 0.5mm
1.1.6 5.6. The heat treated (Head hardened) rail hardness at top surface of rail head shall be
330BHN within a tolerance of + 20BHN. The hardness at a depth of 12.0mm from the
top surface of head at mid-section of rail face will be in the range of 290-310BHN and
260-280BHN at the depth of 15.0 mm. The variation of hardness from top surface up
to a depth of 15.0mm shall be gradual. Sudden variation in hardness of more than
20BHN/mm shall not be allowed as measured at every 3mm. Nature of test : Fig. 8 at
clause 19.2.3 of IRS-T-12-2009 (Latest revision). The test shall be performed in
accordance with IS: 1500 (Part-I)-2019
6. C.I. Chairs: The C.I. Chairs shall conform to gray cast iron Gr. FG-220 of IS: 210-
2009 (Reaffirmed 2020). The Part number, month/ Years of cast and the firms initial
shall be as cast on each of them.
7. M.S. Brackets: The M.S. Brackets shall conform to the requirements of Gr. E250
Quality B0/BR* of IS: 2062 -2011 (Reaffirmed 2016).
8. High Tensile Bolts & Nuts: The High Tensile Bolts used for assembly of Fabricated
Stock rails shall be of Gr.10.9 of IS 1367 (Part- 3): 2017, for Nuts shall be Gr.10 of
IS: 1367(Part- 6):2018, IS: 3757-1985 (Reaffirmed 2019).
9. Track Bolts and Nuts: The Track Bolts and Nuts shall conform to IRS/T-23-1967 or
latest version.
10. Single Coil Spring washers: The Single Coil Spring washers shall conform to
IRS/T-42 and Drg. No. T-10773.
11. Hardened Washer: Hardened Washer shall conform to IS: 6649-1985 (Reaffirmed
2015).
12. Galvanized Plate Screw: Galvanized Plate Screw shall conform to IRS: T 16- 2019.
13. Plain Washer and Split pin: Chemical composition of Plain Washer and Split pin
shall conform to Gr. E250 Quality B0/BR* of IS: 2062 -2011 (Reaffirmed 2016)
In addition to above, IRS Specification T-10 shall also be followed.
* Material grade B with Charpy impact test at room temperature (BR) can be used, if
there is no mutual agreement between the manufacturer and purchaser for Charpy
impact test.
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