INSPECTION & TESTING OF ELASTIC RAIL CLIPS: Guidelines for inspection of raw material, Technical specification of finished clips

INSPECTION & TESTING OF ELASTIC RAIL CLIPS

Functions of elastic rail clips (ERC)

1. It is suitable for modern track & it’s requirements

2. It with stand vibrations induced in track

3. It sustain static and dynamic cyclic stresses

4. It provide creep and torsional resistance and keep rail in position

5. It is able to resist lateral forces

6. It has longer service life with low cost of maintenance

Over view on development of elastic rail clips ERC

1.  RDSO/T-1892- Elastic Rail Clip with round toe (Toe load 645-800kg) -Developed in around 1975

2. RDSO/T-3700- Elastic Rail Clip with flat toe (Toe load 645-800kg)- Developed in around 1988

3. RDSO/T-3701- Elastic Rail Clip Mk-III with flat toe (Toe load 850-1100kg) Developed in around 1988

4. RDSO/T-3722- Elastic Rail Clip Mk-II with flat toe (for MG track) (Toe load 700-900kg) Developed in around 1988

5. RDSO/T-6254 & 6255- Anti-theft Elastic Rail Clip (Toe load 850-1100kg) Adoption in around 2007

6. RDSO/T-5919 – Elastic Rail Clip Mk-V (Toe load 1200-1500kg)

Introduction/salient features of ERC Mk-III

Specification: IRS/T-31-1992

Raw Material: 20.64 mm dia. (Gr. 55Si7 of IS: 3195)

Drawing No.: RDSO/T-3701

Gauge Drg. No.: RDSO/T-3745 & 3746

Drawings for elastic rail clip Mk-iii & anti theft elastic rail clip 

1. RDSO/T-3701 Elastic Rail Clip Mk-III with flat toe for 60 kg UIC/52 kg Rail Section.

2. RDSO/T-3746 Dimension Checking Gauge for Inspection of ERC-Mk-III with flat toe (Drg. No. RT-3701

3. RDSO/T-3745 Fixture for Application and deflection test for ERC-Mk-III with flat toe (Drg. No. RT-3701)

4. RDSO/T-3935 Fixture for holding ERC-Mk-III for angle checking

5. RDSO/T-6254 Anti-theft ERC for 60 kg/52kg Rail section with circlip & 6255 System of quality control

At RDSO Level

a) Development of Vendors

b) Periodical Reassessment of Vendors

c) Consignee end Picking of Samples

d) Special Quality Audit of Vendors

At Zonal Railways Level

a) Inspection & testing of raw material before manufacturing of product.

b) Inspection & testing of product before dispatch to consignee.

At RDSO Level

a) Development of Vendors

– Infrastructure Verification

– Gauge & QAP approval

– Sample collection & testing at RDSO

– Approval for two years in Part-II category subject to inspection & passing of initial 20,000 clips by RDSO

– Upgradation to Part-I after supply of two lacs pieces, 15 months after date of last I. C. & satisfactory feedback of performance

b) Reassessment of approved vendors

– For the purpose of extension of approval of vendors reassessment is done by RDSO every three years

c) Consignee end Picking of Samples

– Two samples per month are picked up from the supplies made at the consignee end.

– Action taken as per consignee end policy.

– Samples selected at random and tested in RDSO

d) Special Quality Audit of vendor

– For restoration of vendor temporarily delisted from vendor list due to failure of consignee end sample, special quality audit is carried out

– Action taken as per consignee end policy.

– Samples selected at random and tested in RDSO

At Zonal Railways Level- Inspection & testing

Inspection of ERC is done in two stages

a. Inspection of Raw Material

(Manufacturing of clips is done after inspection of raw material for ERC)

b. Inspection of finished clips

Inspection of Raw Material

– It is done by consignee zonal railway. Firm submit call letter for inspection after receipt of raw material from RDSO approved suppliers.

Documents & records

– Only original invoice of raw material i.e. buyer/purchasers copy containing. 

Following shall be accepted as proof of purchaser of raw material from approved source.

1. Name & address of supplier .

2. Name and address of purchaser

3. TC no.

4. Date

5. Weight/quantity

Guidelines for inspection of raw material

– Test certificate (TC): Test certificate issued by raw material supplier should be checked

– Above two documents interlinked through reference of Invoice no.

– Test certificate (TC) & Invoice of raw material

TC from of the RDSO approved raw material firm contains values for all the prescribed parameters for each heat of raw material along with the heat number, colour code & weight of consignment.

The invoice or delivery challan from the RDSO approved raw material manufacturer shall also be referred along with TC.

Test parameters of raw material

– Chemical analysis,

– Grain size,

– Inclusion rating,

– Hardness,

– Depth of decarb,

– Freedom from defects &

– Dimensions ( of bar-diameter only)

Technical specification of raw material

• Steel:

Silico manganese spring steel (as rolled bars, grade: 55si7 as per IS: 3195-1992,

Section: 20.64mm Dia. with tolerance of +1.0% & – 0.8%

• Chemical composition: as per IS:228

Range

– Carbon 0.50 – 0.60%

– Manganese 0.80 – 1.0%

– Silicon 1.50 – 2.0%

– Sulphur 0.04 (max.)

– Phosphorus 0.04 (max)

• Grain size:

6 or finer as per IS: 2853-1964

• Inclusion rating:

Not worse than 2.5 a,b,c,d (thick/thin) as per IS:4163:2004

• HARDNESS:

Approx. 270 BHN or its equivalent in HRC or HV scale

• Depth of decarburisation:

0.15 mm (partial+ complete) at 100M Mag.

• Freedom from surface defects:

Shall be reasonably smooth, free from distortion & harmful defects which may impair serviceability.

Manufacturing of clips

• The clips shall be manufactured from as rolled bars by hot forming & shall be subsequently oil hardened and tempered to give uniform hardness across the section.

• The clips shall conform to the requirements of drawing and all tests stipulated in the specification.

• Inspection of finished clips

• It is done before acceptance of clip by consignee zonal railway. Firm submit call letter for inspection in proper format to Inspecting Official.

Following points should be checked before commencement of inspection

Validity of:

Firms approval

Purchase order/contract

Approved inspection gauges.

Calibrations of testing/ measuring equipment as per laid down frequency & through specified agency wherever applicable.

ISO certificate

Records of:

Internal inspection as per QAP (sign them).

Raw material inspection, consumption vis-à-vis production.

Temperature graphs of manufacturing.

General:

Availability of trained workmen

Upkeep of the factory premises

Test parameters of finished clip

• Finished product

– Chemical,

– Inclusion rating,

– Depth of decarb,

– Freedom from defects

– Hardness

– Dimensions (of product – as per inspection gauge)

– Application & deflection

– Toe load

Technical specification of finished clips

• Steel:

Silico manganese spring steel (as rolled bars) , grade: 55si7 as per is:3195

Section: 20.64mm dia. With tolerance of +1.0% & – 0.8%

• Chemical composition as per IS:228

Range Tolerance

– Carbon 0.50 – 0.60% + 0.03%

– Manganese 0.80 – 1.0% + 0.04%

– Silicon 1.50 – 2.0% + 0.03%

– Sulphur 0.04 (max.) + 0.005%

– Phosphorus 0.04 (max) + 0.005%

• Inclusion rating:

Not worse than 2.5 a,b,c,d (thick/thin) as per IS:4163:2004

• Hardness:

40-44 RC, 380-435 HV or 375-415 HB

• Depth of decarburisation:

0.25mm (partial + complete) at 100 Mag.

• Freedom from surface defects:

The clips shall be reasonably smooth, free from distortion & harmful defects which may impair serviceability.

Specified characterstics of ERC Mk-III to RDSO drg. No. RDSO/T-3701

• Contact length of surface of flat toe

Major Axis ≥ 28.0 mm, 

Minor Axis ≥ 9.5 mm

• Deflection – 13.5 mm

Toe load – 850-1100kg

Approx. Weight – 0.91kg

Dimensions – As per inspection gauge drawing

Reference documents

1. IRS specification for elastic rail clips serial no. T-31/1992 (latest with corr.2)

2. All IS-Codes given in spec. IRS/ T-31-1992

3. Product drg. No. RDSO/T-3701

4. Gauge drg. No. RDSO/T-3745 & RDSO/T-3746

5. Quality Assurance Programme (QAP) approved by RDSO

Marking on heel of clips

All clips shall bear clear inscription of stamp as per specification at the heel of the clip to indicate manufacturer’s initial (xx), last one digit of year of manufacture (y) and lot number of the corresponding heat in a particular year (z).

Inspecting official should ensure about clear marking/ stamping during inspection.

Packing and sealing

Before packing, the clips shall be protected with one coat of boiled linseed oil or any other rust-preventing compound approved by the purchaser.

After acceptance of offered material, bags should be stitched with knotless heasian thread and sealed (with lead seal) by inspecting official before dispatch

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