MODERN TRACK STRUCTURE INSPECTION OF LWR Sivakumar A

MODERN TRACK STRUCTURE & INSPECTION OF LWR Sivakumar. A Professor Works/IRICEN/PUNE 7420041125 sivakumar@iricen. gov. in

ROUTE CLASSIFICATION Classification of Lines–on the basis of the future maximum permissible speeds (1) Group ‘A’ – Speeds up to 160 km/h (2) Group ‘B’ – Speeds up to 130 km/h (3) Group ‘C’–Suburban Sections of Mumbai, Delhi, Chennai and Kolkata. (4) Group ‘D’ Special – Speeds up to 110 km/h & the annual GMT is 20 or more. (5) Group ‘D’– Speeds up to 110 km/h & the annual GMT is less than 20 GMT. Note – While classifying route, in case of double and multiple lines, annual GMT on each line shall be considered separately and classified based on the highest GMT on any one line. (6) Group ’E’ – All other Sections and branch lines with speed up to 100 km/h.

Track Structure for speeds beyond 110 kmph of Passenger carrying train on BG IR Speed Rails Sleeper Density Ballast Cushion Switch Crossing SEJ Bridge Sleepers Level Crossings Fencing Curves Speed above 110 kmph and up to 130 kmph 60 kg 90 UTS PSC at 1660 Total 300 clean 150 Thick Web Switches on all turnouts CMS Improved Type H – Beam Sleepers/Composite sleepers Interlocked All along the track Shall be suitably realigned with proper transitions. Maximum permissible cant of 165 mm, subject to the consideration of maximum cant excess for the slowest moving train. survey of each curve including the fixed installation and thereafter realignment should be undertaken keeping all the constraints in view. With a cant deficiency of 100 mm, the maximum permissible speed on 2 degree curve works out to be 130 kmph for 165 mm cant.

Track Structure for speeds beyond 110 kmph of Passenger carrying train on BG IR Speed Rails Sleeper/ Density Ballast Cushion Switch Crossing SEJ Bridge Sleepers Level Crossings Fencing Curves Speed above 130 kmph and up to 160 kmph 60 kg 90 UTS PSC at 1660 - Wider and Heavier PSC sleeper - used during renewals Total 350 clean 150 Thick Web Switches on all turnouts Weldable CMS Improved Type H – Beam Sleepers/Composite sleepers No Level crossing All along the track Shall be suitably realigned with proper transitions. Maximum permissible cant of 165 mm, subject to the consideration of maximum cant excess for the slowest moving train. survey of each curve including the fixed installation and thereafter realignment should be undertaken keeping all the constraints in view. With a cant deficiency of 100 mm, the maximum permissible speed on 1 degree curve works out to be 160 kmph for 165 mm cant.

Concrete Sleepers Mono-block & twin-block Types - IR Uses the Mono-block type Provides longitudinal, lateral stability required for LWR. Manufactured to RDSO specification No IRS: T-39 (Plain Track) & IRS: T-45 (Turnout sleepers). Due to the Flat bottom are suitable for mechanised tamping. Can be identified by the drg no. and code of sleeper manufacturer with year of manufacture engraved on the top end surface of sleepers. Tested for electrical resistance at the time of manufacture & marked by paint with “FTC” - Fit for Track Circuiting and “NFTC” - Not fit for track Circuited location. If used in yards with FP/SWR, sleeper spacing at FP joint shall be kept uniform, preferably with 1 m long fishplates at such joints.

COMPOSITE SLEEPERS Made up of polymer composite materials. Based on the Polymer composite, classified as : (a) Fiber reinforced polymer composite - polymer reinforced with fibrous glass or other fibers, including polymeric fibers. (b) Particle reinforced polymer composite - polymer modified with dispersed small particles to enhance particulars physical and / or mechanical properties. (c) Hybrid composite – a composite that incorporates two different reinforcement fibers or other structural components (e. g. a concrete steel and polymer combination). Manufactured to “RDSO’s Provisional Specifications for Composite Sleepers (2014)”. Designed primarily for, but not limited to, Girder Bridges.

APPROVED FITTINGS TO BE USED ON COMPOSITE SLEEPERS Drawing No / part No 60 kg/m Rail 52 kg/m Rail MS Bearing plate RDSO / T-1033 RDSO /T -10671 Rail screw (For use with bearing plate) RDSO / T-1035 RDSO / T -10675 Rail screw (For use without bearing plate) RDSO / T-1034 RDSO / T 10673 Hook Bolts B 003/ M Plate Screw (For fixing walkway) T-10679 Fittings

Elastic Rail Clip (ERC): Manufactured from Silicomanganese Spring steel by RDSO Approved Suppliers as per RDSO specification IRS-T: 31. They offer a designed Toe load at design deflection. ERC type ERC-J Mk- III Mk-V Anti-theft RDSO Drg Toe load Toe def. Dia. Approx. no. (kg) (mm) Weight (kg) RT-8258 650 8. 5 20. 64 1 RT-3701 850 -1100 13. 5 20. 64 0. 91 RT-5919 1200 -1500 13. 5 23/20. 64 1. 08 RT-6254 850 -1100 13. 5 20. 64 0. 937

Grooved Rubber Sole Plate (GRSP): Manufactured from rubber compound to RDSO specification No IRS –T - 47, Absorbs high frequency vibrations, shocks & reduces noise. Composite GRSP with two layers of different types of rubber, for improved performance, developed, the top layer having higher modulus of elasticity (harder) while bottom is of softer material. RDSO specifications for CGRSP (provisional) - RDSO / M&C / RP-198 / 2006 for 6. 2 mm & RDSO / M&C / RP-200 / 2007 for 10 mm. The harder layer should be kept in contact of Rail. Thus, the surface of CGRSP where manufacturer’s initials are embossed should be placed on rail seat, facing up.

Nylon Cord Reinforced GRSP: Specifically designed for use below Crossings of Turnouts conforming to “RDSO specifications for 6 mm thick Nylon Cord Reinforced GRSP for placing beneath rails at turnouts, Provisional 2007(RDSO/M&C/RP-201/2007)”. DRG. No DESCRIPTION RT-7014 to 6 mm thick nylon cord reinforced GRSP for placing 7021 beneath crossing portion in 12 turnouts on PSC sleepers

Liner Used in conjunction with GRSP/ CGRSP & on both sides of the rail foot to achieve the correct track gauge to provide for the correct deflection of the ERC for the designed Toe load. Combination liners also allow flexibility to use lighter rail sections on the sleepers meant for heavier rail section Liners are made of two materials viz. , Glass filled Nylon (GFN) liners (as per “RDSO specifications IRS: T-44”) generally used in track-circuited locations Metal Liners (as per “RDSO specifications for Metal liners – Provisional 2013”) Cut liners used with ERC J clip at FP Joint/ Glued Joint

Ballast Crushed Stone ballast to be used on all lines including P&C - to RDSO specifications for Track Ballast No. IRS -GE -1, June 2016 with latest amendments. Depths of Ballast Cushion below bottom of sleepers at rail seat In case of For all routes 300 mm Track Renewals (CTR/TSR) (Where possible 350 mm shall be provided) All Doubling, GC & New Line construction works 350 mm Loop Lines 250 mm For permissible speed up to 50 km/h. 300 mm Private and Other Sidings For permissible speed more than 50 km/h 350 mm Clean ballast cushion at all times for mechanised maintenance under the rail seat of the PSC sleepers shall not be less than 150 mm. Increase in ballast cushion to make up the recommended depth will be carried out during CTR /TSR or programmed DS of track. Special attention - locations such as Br / LC & tunnel approaches so as to ensure full ballast section for six rail lengths on either side.

Ballastless Track (BLT) Ballastless track can be provided, selectively, at locations having difficulty in maintenance of conventional track such as Tunnels, Viaducts etc. (1) Ballastless track for Speed up to 110 km/h shall be laid with Indigenous Fastening System (BLT-IFS) as per RDSO specification CT-31, “Guidelines for Construction of Ballastless Track with Indigenous Fastening System (BLTIFS) (provisional)” to RDSO Drg No T-8304 & RT-8305 (2) Ballastless Track for Speed up to 50 km/h shall be laid with Indigenous Fastening System (BLT-IFS) as per RDSO specification CT-31 B, “Guidelines for Construction of Ballastless Track for Washable Apron on Loop Line” to RDSO Drg. No. T-8777 & RT-8778

Switch Expansion Joint An expansion joint installed at each end of LWR/CWR to permit expansion/contraction of the adjoining breathing lengths due to temperature variations. Normally, SEJ are provided for same rail sections. Combination SEJ shall be provided between the junction of two different rail sections such as 52 Kg rail and 60 Kg rail. RDSO Drawing No Rail section Maximum Design Gap IRS design RT-4160 52 Kg/m 80 mm IRS design RT-4165 60 Kg/m 80 mm Improved SEJ - RT- 6902 60 Kg/m 80 mm (Single Gap) Improved SEJ - RT- 6914 52 kg/m 80 mm (Single Gap) Improved SEJ - RT- 6922 60 Kg/m 65 mm (Double Gap) Improved SEJ - RT- 6930 52 kg/m 65 mm (Double Gap) Combination SEJ to RDSO Drawing No. RT-6782 with 80 mm gap between 52 Kg rail and 60 Kg rail shall be used

Commonly used P&C Layouts Rail Section and sleeper Angle of Crossing 52 Kg/m Rail on PSC sleeper 60 Kg/m Rail on PSC sleeper 1 in 8½ 1 in 12 1 in 16 1 in 20 RDSO Drawing No. Complete Layout Switch sub Assembly Crossing sub Assembly RT-4865 RT-4965 RT-4732 RT-4218 RT-5961 RT-5858 RT-4866 RT-4966 RT-4733 RT-4219 RT-5962 RT-5859 RT-4867 RT-4967 RT-4734 RT-4220 RT-5963 RT-5860 In case of LWR/CWR taken through P&C, the provisions of RDSO report no. CT - 48 shall be followed.

INSPECTION IN LWR

What is LWR inspection? (a) SEJ Gap measurement (b) Frequency – 14 times a year? ? (c) Tightness of fittings (d) Zero Missing fittings (e) Oiling and greasing of SEJ (f) Squareness of sleeper at SEJ (g) Movement at centre of LWR / CWR. (h) What else? ? ? Sorry, this is not what is meant by inspection of LWR.

THERMAL FORCES IN RAIL • Temperature changes cause expansion of the rail. If rail is restricted from expansion, thermal forces are built up within the Rail. • The thermal force (P) is calculated by P=EA t where, P = Thermal force in the rail (kg) E = Modulus of elasticity of rail steel (2. 15 x 106 kg/sq. cm) = Coefficient of linear expansion of steel (1. 152 x 10 -5/0 C) A = Area of cross section of the rail (sq. cm) 0 t = Variation of rail temperature from td /to ( C) This Thermal force is resisted by the track structure.

RESISTANCE TO THERMAL FORCE BY TRACK COMPONENTS Resistance by the track (R) is due to • Rails, which are fastened to sleepers with fittings • Sleepers are embedded in Ballast • Ballast is laid on stabilized formation and is well compacted Thus, a track with all its components, acts as a composite structure which offers resistance to the free expansion / contraction of rail on account of thermal forces.

LONG WELDED RAIL Understanding the delicate balance between the Thermal force, P and Resistance offered by the track, R, at all times is the key. INSPECTION OF LWR, HAS TO COVER ALL THESE ASPECTS FOR ITS EFFECTIVE PERFORMANCE.

What are the factors governing P P=EA t Where, the only variable that can be controlled by Engineers is t depends on destressing temperature td and prevailing rail temperature tp td should be within the range as under Temperature Zone I, II&III For all rail sections Temperature Zone IV i)52 kg and heavier II)Other sections tm to tm+5°C to tm+10°C tm to tm+5° . t

What are the factors governing P The reliability of t ( td / tp ) depends on thermometer. Para 332 (2) of new IRPWM states “Where a number of thermometers are used to measure the rail temperature at one place, as in case of laying of LWR, de-stressing etc. or during routine tools inspection at office of SSE/ P Way, any of thermometer showing erratic readings, appreciably different from the other adjoining thermometers, shall be considered as defective”.

What are the factors governing R Resistance by the track (R) is due to • Rails, which are fastened to sleepers with fittings • Sleepers are embedded in Ballast • Ballast is laid on stabilized formation and is well compacted We need to check, if any past action, has reduced the contribution made by any of the components in reduction in Value of R.

What are the factors governing R Ballast: Most important contributor to track resistance Less ballast Poor Quality of Ballast, Poor consolidation Low Cess, thereby rolling down of Ballast Leads to reduction in R value significantly.

What are the factors governing R Rails: - Wear at rail foot ends Can cause reduction in deflection offered to ERC, Thereby reduction in toe load. This affects adversely the concept of “LWR Track Frame” or “Composite Track Structure” Leading to Creep / differential Creep.

What are the factors governing R Sleepers: any signs of wear in rail seat, crack in sleeper or rounding of sleeper bottom These factors affect Toe load, (Creep) inherent strength of sleeper to hold rail, Poor retentivity of ballast packing.

What are the factors governing R Fittings: Important component to achieve track frame concept ERC: Affects toe load directly (Creep) If not driven correctly, i. e. , if end of central leg not flush with end of insert Liner: If crushed, broken, corroded Missing, placed upside down, displaced etc Leads to reduction in Toe load. (Creep)

What are the factors governing R GRSP: If crushed, missing or displaced out of position Else GRSP/ CGRSP shall lead to premature crushing and Failure at Site (Creep). Causes Permanent damage to rail seat Very costly damage

What are the factors governing R CREEP The least noticed / considered / monitored factor in a LWR However, probably the most important factor in a LWR A RDSO Study points out that a creep of 50 mm into or out of a LWR segment of 500 M length causes the td to change by about 10° Celsius. Creep post are now available only at centre of LWR and at SEJ, LWR is now from station to station, more variations within this block section length are also available.

CREEP IN LWR 500 m Segment 1 Segment 2 500 m Segment 3 500 m Segment 4 Segment 1 – Creep from both adjoining segments into this segment – if total creep is more than 50 mm, td gets lowered by about 10° Celsius, buckling tendency increases for same book value of td Segment 2 – Creep into and out of this segment is same, thus effective creep is zero, td remains unaltered Segment 3 – Creep from both adjoining segments out of this segment – if total creep is more than 50 mm, td gets increased by about 10° Celsius, rail fracture tendency increases for same book value of td Segment 4 – Creep into and out of this segment is same, thus effective creep is zero, td remains unaltered.

LWR through P&C on 1 in 12 turnout on PSC Sleeper with TWS & Weldable CMS crossing on run through line / main line with special arrangements Track structure - LWR on Min 60 kg/90 UTS rails, PSC sleeper 1660, ERC Mk-V. TWS on PSC sleepers with elastic fastenings & 25 mm dia bolts in heel & distance blocks, with ERC MK V on P&C layout to arrest creep. Use of a specially designed Anti Creep Device behind heel of switch in tongue rail portion of turnouts to detect Creep, if any. Welding of tongue & lead rail joints instead of machined joint, Use of weldable CMS crossing, with all joints welded SEJs, if required, provided such that T/O not in breathing length zone, SEJs to be at least 150 m from the SRJ/ Heel of crossing Standard Ballast profile, Min cushion - 300 mm with clean cushion of 150 mm at all times. Stable formation, ZMF, Zero loose fittings in LWR including turnout. Regular monitoring of toe load - remedial measures in case toe load is less than 1000 kg.

LWR through P&C on 1 in 12 turnout on PSC Sleeper with TWS & Weldable CMS crossing on run through line / main line with special arrangements Deep screening at the time of installation of LWR through turnout if the stipulated ballast cushion is not available. CREEP MEASURED REGULARLY AT LEAST ONCE A MONTH BY PROVIDING CREEP POST AT FOLLOWING LOCATIONS, a) Creep at ATS for stock rail & tongue rail tip. b) Creep in crossing portion at ANC. c) Creep in the central portion of LWR. d) Creep in lead portion. e) Creep at 20 m from ATS at approaches. f) Creep at 50 m beyond ANC at approaches SEND QUARTERLY REPORT TO RDSO

Inspection of LWR requires less maintenance, but intensive inspection at supervisory and officer’s level is required Ballast section shall always be complete. Checked, especially at pedestrian / cattle crossings, curves, approaches of LC, P&C and bridges. Cess level should be correctly maintained. Replenishment of ballast before the onset of summer. Inspection shall be more frequent in the AN during summer Knowledge of staff regarding prescribed maintenance practices checked and the work is done accordingly.

Inspection of LWR USFD examination of rails should not be in arrears. Defective rails/welds should be replaced expeditiously. Inspections of gaps at SEJ and creep/movement at central portion of LWR/CWR by Permanent Way officials would be done as per prescribed schedule by JE/SSE (P. Way) Subsection, SSE (P. Way) I/C and ADEN. Check for creep in as many locations as possible. If creep posts are not available, creep indication on liner seat can be a tell-tale help to identify creep. During TRR / TSR, & Service, Complete & Effective Fitting (ZMF? ) to be aimed at and achieved.

Inspection of LWR Inspections of gaps at SEJ and creep/movement at centre of LWR/CWR by Permanent Way officials as per following schedule: i) SSE-In-charge/SSE Sub-section: - (ACS 15) a) Every fortnight during two coldest & two hottest months of year at about min and max temperatures alternately by SSE In-charge and SSE Sub-section. b) Alternately once in two months during other months of the year. ii) Assistant Engineer: At least once in six months, preferably during coldest and hottest months.

Inspection of LWR Important Points to be Noted: • • • The gap shall always mean distance between reference line to the tip of stock rail / Tongue rail. In case of DG design, 2 reference marks shall be erected at site Sleeper spacing at SEJ shall be ensured, 700 mm for Conventional SEJ, 600 mm for SG and DG ALWAYS REMEMBER THE DELICATE BALANCE BETWEEN P and R.

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