Railway OHE Fittings

Two: item 3100659 — galvanised steel fittings, and item 3100653 — copper fittings. Between them the schedules cover 65 sub-items, each with its own sub-item ID, mark number and ETI/OHE drawing. RDSO and the Railway purchase system read an enquiry by sub-item ID, not by description, so if you are sending a bill of materials, send the IDs and the answer comes back against the right part.

The steel fittings that hold the overhead equipment in place and keep the contact wire at tension: anti wind straps and clamp straps (marks 2502, 2503, 2504), galvanised MS U-bolts (2113, 2133), packing pieces (5067), double end studs with nuts (5097, 5097-3), guide plate weights (5096), counter weight rods, plates and eye rods (5098, 5099, 5099-1, SK-588), compensating and equalising plates (5191-1, 5191-2, 5192-1, 5192-2, 5193, 5194, 5194-1, 5195, 5195-2), guy rods (5005-1) and earth electrodes. The table on this page names them against their sub-item IDs.

The current-carrying fittings on the overhead equipment, including terminal lugs to suit the conductor (reference no. 6) and the associated connection parts carried on the ETI/OHE/P/1310 and 1311 drawing sheets. Copper fittings are a separate item with their own schedule of technical requirements and their own machining and testing expectations. Copper chemistry is checked on the spectrometer in our own laboratory before machining.

The ETI/OHE/P series — the Railway Electrification traction drawing sheets. A single sheet often carries several parts: ETI/OHE/P/2341 carries 2341 through 2344; ETI/OHE/P/5004/5/6-1 carries 5004, 5005 and 5006-1; ETI/OHE/P/6075/6076 carries both clamps; ETI/OHE/P/5001/5001-1 carries both variants; ETI/OHE/P/1310 carries part 1311. Others carry only the base part — ETI/OHE/P/5191 and 5192 do not carry their -1 and -2 variants, which are separate sheets. We work to the drawing, and where a drawing and a bill of materials disagree, the drawing wins.

The CORE schedules of technical requirements: STR-20 for galvanised steel fittings and STR-17 for copper fittings. They set out the plant, the testing facilities and the quality system a manufacturer has to hold — chemical analysis, tensile testing, hardness, coating thickness, dye penetrant, calibration, traceability from heat number to finished part, a quality assurance plan, and a rejection and field-failure system. The table on this page sets each requirement against what is actually on our floor.

Optical emission spectrometry for steel and copper chemistry in a dedicated spectrometer room, a universal testing machine for tensile and proof load, hardness testing, calibrated coating thickness gauges, dye penetrant, precision weighing for coating mass, and dimensional inspection against the drawing. Our laboratory is not NABL-accredited; where a specification requires NABL type-test reports, that testing is arranged with an accredited laboratory against the order. We say so rather than letting it surface at inspection.

Hot-dip galvanized in our own kettle at Jangalpur to IS 2629 and IS 4759, at 75–85 microns — about 610 g/m² of zinc — read on a calibrated dry film thickness gauge, batch by batch. Fittings and small hardware are the items where coating decides service life, and because the galvanizing is on our own floor rather than sub-contracted, the coating record and the fabrication record come from the same works.

Yes, and from the same floor. We are RDSO approved for railway structures and manufacture OHE masts, portals and brackets and steel channel sleepers — the sleepers since 2001. Structures and fittings go into the same kettle, which is why the coating on the fitting matches the coating on the mast it bolts to. See railway OHE structures and steel channel sleepers.

The sub-item IDs or the mark numbers, the quantities, the coating figure the specification states, the inspection agency, and whether the scope is ex-works or delivered. We mark the bill of materials line by line and a formal quotation typically goes back within 48 business hours.

Because a railway buyer searches by item code and mark number, not by marketing copy. An enquiry for mark 5192-1 is not an enquiry for “OHE fittings”, and a page that does not name the part cannot answer it. Every code, mark and drawing reference on this page can be checked against the Railway’s own schedules.