PART IITRACK COMPONENTS RAILS 1 RAILS 10 1

PART II-TRACK COMPONENTS : RAILS 1 RAILS : 10 1. 1 Rail, different types of rail section, various types of standard of loadings. 2 1. 2 Sectional properties Standard sections, grade, UTS & service life, classification, Rolling marks. Colour coding of rails 2 1. 3 Visit to Model room for different types of rails. 1 1. 4 Instruction for handling of rails. 2 1. 5 Straightening of rail kinks by Jim crow & precautions while using Jim Crow. 1 1. 6 Corrosion of rails & methods for anticorrosion treatment of Rail. 1 1. 7 Wear of Rail & its causes. 1

PART II-TRACK COMPONENTS : RAILS 1. 7 Wear of Rail & its causes. 1

WEAR & ITS CAUSES Due to rail wheel interaction the original dimension of rail profiles becomes less. Mainly there are two types of measurable wear; Vertical Wear Lateral Wear Due to wear there is %age loss of section by weight

Causes of Rail wear 1) Corrosion and rusting (Generally noticed on web & foot of rail) Locations Prone to corrosion : i) Platform lines. ii) Sidings where corrosive goods are dealt. iii) Tunnels and damp cuttings. iv) Coastal area. v) Industrial belts.

Contd. … 2. Wear on Rail Table : � Normally of very small order. � Amount of wear increases with heavy traffic density as in suburban section. 3. Flattening of rail table: § Mostly occurs on the inner rail of a curve. § Indication of over loading

Contd. … 4. Wear on Gauge Face: q Noticed on outer rail of a curve. q Due to heavy pressure from the wheels which results in the running edge becoming worn or ‘side-cut’. q Specially in suburban sections where multiple unit coaches are provided.

Reducing side wear on rails(Gauge face of outer rails) – (a) On sharp curves where the tendency of wear on the outer rail is noticeable, lubricators should be installed as per Para 424 of IRPWM or hand lubrication of gauge face should be done, care being taken not to apply the lubricant on the top of the table. In case of hand lubrication, the Divisional Engineer may decide frequency of lubrication duly considering local conditions and traffic on the line.

Reducing side wear on rails; Increased life can be obtained by turning the rails when side wear reaches the permissible limit. At the time of turning, matching of rail ends on the gauge face should be ensured. Spot renewals should not be carried out with new rails particularly, if the heads of the existing rails are worn badly. These should be spot renewed with matching sections of serviceable rails

Wear due to corrosion– Corrosion beyond 1. 5 mm in the web or foot may be taken as the criterion for wear due to corrosion. Existence of the localized corrosion such as corrosion pits, especially on the underside of the foot and liner biting etc. on rail foot, act as stress raisers for the origin of fatigue cracks and would necessitate renewals.

VERTICAL WEAR

LETERAL WEAR

Limiting Loss of Section– The limiting loss in rail section, as a criterion for recommending rail renewals shall be; Rail Section Loss in section in percentage 52 kg/m 6 60 Kg/m 7

Limit of Vertical Wear Gauge Vertical Rail Section Wear B. G. . . 60 Kg. / metre. . 52 Kg. / metre. . 90 R. . 75 R. . 60 R. . 13. 00 mm. 8. 00 mm. 5. 00 mm. 4. 50 mm. 3. 00 mm M. G. . .

LATERAL WEAR SECTION GAUGE B. G CURVES M. G B. G STRAIGH T CATEGORY OF TRACK Group ‘A’ & ‘B’ Routes Group ‘C’ & ‘D’ Routes Group ‘Q’ & ‘R’ Routes Group ‘A’ & ‘B’ Routes Group ‘C’ & ‘D’ Routes LATERAL WEAR Group ‘Q’ Routes 6 mm 8 mm 10 mm 9 mm 6 mm 8 mm

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