Codification of rail and weld defects:
Information regarding the type and nature of rail failures and their service conditions is primarily obtained through personnel responsible for maintenance of permanent way and it is of utmost importance that they are familiar with the various types and nature of rail defects and their possible causes to enable them to report the rail failures accurately. With this objective in view, it is necessary to devise a suitable coding system for reporting rail failures.
1.3.1UIC has adopted an Alphanumeric system of codification of rail failures. In view of its international status and the facility afforded for computerized statistical data analysis, this system has been adopted by Indian Railways for reporting rail failures. The code for reporting rail failures consists of two parts viz first – Alphabetic, consisting of three code letters and second numeric, consisting of three or four digits.
1.3.1.1 First part of the code ± Alphabetic
(a) First code letter indicates the type of rail:
| O | indicates | plain rail |
| X | indicates | point & crossing rail |
(b) Second code letter which follows the first code letter, indicates the reasons for withdraw of rail. Thus,
| F | indicates | Fractured rail |
| C | indicates | Cracked rail |
| D | indicates | Defective rail other than F&C |
(c) Third code letter which follows the second code letter, indicates probable cause of failure or rail. Thus:
| R | indicates | Cause inherent in rail (attributable to faults in the steel making stage and / or its rolling into rails). |
| S | indicates | Fault of rolling stock |
| C | indicates | Excessive corrosion |
| J | indicates | Badly maintained joint |
| M | indicates | Other maintenance conditions (Defects which develop due To ineffective maintenance or delayed renewal of rails). |
| D | indicates | Derailment |
| W | indicates | Associated with welding defects (through or adjacent Within 100 mm of a welded joint) |
| O | indicates | Other causes |
1.3.1.2 Second part of the code ± Numeric :
This part of the code consisting of three or four digits indicates the location of the failure in the rail as well as its characteristics :
(a) The first digit indicates the location of rail failure (head, web or foot)
(b) The second digit indicates:
(i) The position in the rail section from which failure has started except where failure is associated with welding.
(ii) In case of welding, the second digit indicates the type of welding.
(c) The third digit is interpreted in relation to the first two digits of the code viz :
(i) If failure is due to internal defect (first digit 4 or second digit 1,3 or 5), it shows the direction of the crack or fracture.
(ii) If failure is due to surface defect (second digit 2 or 5), it indicates the nature of defect.
(iii) If failure is by damage (first digit 3), it indicates the cause of the damage (details have been given in succeeding pages)
(d) The fourth digit gives further details.
1.3.1.3 The summary of codification of rail and weld failures is given as under:
(a) First Part – Alphabetic codes
| 1st letter | 2nd letter | 3rd letter |
| Type of railO-Plain rail X-Points & Crossings rail | Reason for withdrawalF-FracturedC-CrackedD-Defect other than F&C | Probable cause of failure R-Inherent in rail S-Fault of rolling stockC-Excessive corrosionJ-Badly maintained joint M-Other maintenance conditions D-Derailment (failure developed later) W-Associated with welding O-Other causes |
(c) Second Part – Numeric codes
| 1st digit | 2nd digit | 3rd digit | 4st digit |
| Location & characteristics | Origin/Type Of welding | i) For internal defects in welding shows direction: if 2nd digit 1,3,5 | Further details |
| 1.Within fishplate limit | 0-Unknown1.within head | 1. Transverse2. Horizontal3. Vertical longitudinal | 1. At rail seat2. Not at rail seat1. Top fillet2. Bottom fillet3. Not at fillet radius |
| 2.Other location | 2. Surface of rail head3. In web5.In foot | 5. Diagonal at hole 8. Diagonal not at holeii) For surface defects it shows nature of defects if second digit 2,3,50. Corrugation1. Shallow surface defect 2. Breaking out3. C rushing continuous4. Battering local 5. Wheel burns9. Lap, seam, roll mark | 1. Short pitch 2. Long corner 1.Running surface 2.Guage corner1. Isolated 2.Repeated |
| 3.Damage done | 0 | 1 Brushing or arcing2 Incorrect machining drilling or flame cutting | |
| 4.Associated with welding | Type of welding1. Flash butt2. Thermit 3. Electric arc joint4. Oxy-acyty lene joint7. Building up8. Traction bond | Direction of fracture1. Transverse 2. H orizontal 5. Diagonal at hole8. Diagonal not at hole | |
| 5.Corrosion | 0 | 0 |
1.3.1.4 On the basis of the system of classification described in para
1.3.1.2, a list of the failure code group to be followed is given as under, along with the meaning of the codes.
| Within fish-plate limits | Elsewhere on rail | Description |
| 100 | 200 | Transverse breakage without apparent origin (i.e. sudden fracture) |
| 111 | 211 | Internal flaw in head, transverse breakage |
| 112 | 212 | Internal flaw in head, horizontal crack. |
| 113 | 213 | Internal flaw in head, vertical longitudinal split. |
| 1211 | 2211 | Head, surface, shallow surface defect (flaking) |
| 1212 | 2212 | Head, surface, shallow surface defect (line). |
| 1221 | 2221 | Head, surface, breaking out running surface (scabbing) |
| 1222 | 2222 | Head, surface, breaking out, gauge corner (shelling) |
| 123 | 223 | Head, surface crushing or battering |
| 124 | 224 | Head, surface local batter |
| – | 2251 | Head, surface, wheel burn isolated |
| – | 2252 | Head surface, wheel burn repeated |
| 1321 | 2321 | Web, horizontal cracks, at top fillet radius |
| 1322 | 2322 | Web, horizontal crack, at bottom fillet radius |
| 1323 | 2323 | Web, horizontal crack, not at fillet radius |
| 133 | 233 | Web, vertical longitudinal splitting (pipe) |
| 135 | 235 | Web, cracks at hole |
| – | 238 | Web, diagonal cracks not at hole. |
| 139 | 239 | Web, lap |
| 1511 | 2511 | Foot, transverse break at rail seat |
| 1512 | 2512 | Foot transverse break starting away from rail seat. |
| 153 | 253 | Foot vertical longitudinal split (halfmoon crack) |
| 301 | – | Damage to rail by brushing or arcing |
| 302 | – | Damage to rail by bad machining, drilling or flame cutting |
| 411 | – | Welding,flashbutt joint, transverse crack |
| 421 | – | Welding, thermit joint, transverse crack |
| 422 | – | Welding, thermit joint, horizontal crack |
| 431 | – | Welding, electric arc joint, transverse crack |
| 441 | – | Welding oxyacetylene joint transverse crack |
| 471 | – | Welding, building up transverse cracking of head across the built up portion |
| 472 | – | Welding, building up, built up part breaks away. |
| 481 | – | Welding, traction bond welding crack, at weld |
| 500 | – | Corrosion. |
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