1. What is Track Maintenance?

Track maintenance is the organised process of inspecting, repairing and upgrading the rails, sleepers, ballast, fastenings and formation so that the track continues to meet the prescribed geometry standards, ensures running safety and provides a comfortable ride at the sanctioned speed.

2. Objectives of Track Maintenance

• Maintain correct track geometry (gauge, alignment, longitudinal level, cross-level, twist)
• Keep rail & sleeper defects within permissible limits
• Preserve resilience & drainage
• Ensure riding comfort & safety
• Minimize overall life-cycle cost

3. Track Components & Their Maintenance Needs

4. Key Specifications (Indian Railway Permanent Way Manual – IRPWM 2021)

• Gauge – 1676 mm (BG), 1000 mm (MG), 762/610 mm (NG)
• Maximum tolerable gauge variation – (+)6 mm / (–)3 mm for BG (Group-A route)
• Alignment deviation on 20 m chord – 20 mm (for 160 km/h)
• Longitudinal level on 3.6 m straight edge – 6 mm (Group-A), 10 mm (Group-D)
• Cant deficiency – 75 mm (BG conventional), 100 mm (with 60 kg 90 UTS rail & CMS crossing)
• Minimum ballast cushion – 250 mm (BG high-speed), 200 mm (BG plain line)
• Pack voids – ≤2% sleepers (plain track), ≤1% (approaches to bridge & points & crossings)
• Frequency of systematic track recording – Once in 2 months (≥110 km/h), quarterly (<110 km/h)

5. Classification of Track Maintenance

A. Routine / Daily Maintenance

• Through packing / measured shovel packing
• Picking up slacks
• Lubrication of rail joints
• Casual renewal of broken sleepers & fastenings

B. Periodic Maintenance

• Machine Packing (Tamping) – 1 cycle / 60 GMT or 2 years whichever earlier
• Deep screening – 1 cycle / 10–12 years (BG), 15 years (MG)
• Track renewal (complete or partial) – based on GMT, UTS rail policy, rail wear index

C. Special Maintenance

• Prestressing of concrete sleepers
• Rail grinding & milling
• Formation rehabilitation
• Pre-monsoon attention (patrolling, destressing of LWR)

6. Track Machines Used

• UNOMAT/SM-IT – for plain track & switch tamping on LWR track without destressing

7. Rail Grinding Strategy (Indian Railways since 1996)

• Preventive grinding – 40–60 MGT or 2 years (BG high-speed)
• Corrective grinding – when corrugation ≥0.15 mm depth
• Target profile – 60E1/52E1/90 USFD compatible profile
• RCF (Rolling Contact Fatigue) control – keep cracks <5 mm

8. Long Welded Rail (LWR) & Maintenance

• Breathing length – 100 m (BG) each end
• Destressing temperature band – td ± 5 °C (td = rail temperature at laying)
• Minimum ballast resistance – 9 t/m (BG) for LWR stability
• Hot weather patrol – when rail temp > td + 20 °C
• Cold weather patrol – when rail temp < td – 30 °C

9. USFD (Ultra-Sonic Flaw Detection) Rail Testing

• Frequency – 4 months (BG main line), 6 months (BG other), 12 months (MG)
• Acceptable defect size – Transverse crack <5% head area
• Action for 5–8% – watch & re-test within a fortnight
• >8% or 20 mm length – immediate removal / closure

10. Historical Milestones

11. Current Status & Recent Updates (2020-24)

• 80% of BG track machine-packed; target 100% by 2027
• Rail Grinding Train (RGT) – 2 imported + 2 made by RDSO/BHEL under “Make-in-India”
• Track Management System (TMS) – GIS-based digital inspection through handheld Android devices
• Smart Patrolling App – live photo with GPS tag, replaced manual log-book
• Ultrasonic Rail Flaw Detection – phased array technology trials on Northern Railway
• Green Initiatives – 100% recycled plastic sleepers (Tata-Ambikapur project) approved for 5 km trial
• T-49 (2023) revised policy – mandatory use of mechanical tamping in approach of all turnouts within 200 m

12. Organisation & Staffing Pattern

• PWI (Permanent Way Inspector) – in-charge of 50–70 km (BG) or 80–100 km (MG)
• Keymen – 1 per 5 km (high-speed), 1 per 10 km (other)
• Gang strength – 12–14 men per km annually for manual maintenance
• Machine gang – 6–8 operators per CSM unit (3 shifts)

13. Safety Drives & Campaigns

• “Safety-Samiksha” – 2022 drive to eliminate derailments through 100% USFD coverage
• “One Minute Safety Drill” – mandatory before every block
• “Track Safety Fortnight” – June & December each year
• IRCA (Indian Railway Conference Association) code revised every 5 years

14. Track Recording & Quality Indices

• Track Recording Car (TRC) – fortnightly for ≥130 km/h, monthly for others
• Q-value (Quality Index) – composite index combining alignment, level, twist, gauge, etc.
  • Q ≤ 20 → Good
  • 20 < Q ≤ 40 → Satisfactory
  • Q > 40 → Needs attention
• Oscillograph car (Oscar) – rides at 5 mm/sec max vertical acceleration for 160 km/h

15. Common Causes of Track Defects

1. Inadequate ballast cushion → poor drainage & pumping
2. Over-driving of spikes → sleeper splitting
3. Improper destressing → kinks in LWR
4. Delayed screening → ballast fouling & wet-bed
5. Skipped USFD → rail fractures in service

16. Cost Indicative Figures (2023 Indian rates)

• Manual through packing – ₹0.12 million per km
• Machine tamping – ₹0.05 million per km (only tamping)
• Deep screening – ₹2.5 million per km
• 60 kg rail renewal – ₹6 million per km (rail + sleeper + fastenings)

17. International Comparison (for GK)

18. MCQs for Practice

1. The maximum permissible gauge variation for BG Group-A route is A) ±10 mm B) +6 mm / –3 mm C) +8 mm / –4 mm D) ±5 mm

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   Correct Answer: B Explanation: For BG Group-A routes, the standard gauge tolerance is maintained between +6 mm and -3 mm.

2. Minimum ballast cushion prescribed for BG high-speed track is A) 150 mm B) 200 mm C) 250 mm D) 300 mm

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   Correct Answer: C Explanation: A minimum ballast cushion of 250 mm is mandatory for high-speed Broad Gauge tracks to ensure proper load distribution.

3. Which machine is used for deep screening of ballast? A) Tamping machine B) DTS C) BCM D) UNOMAT

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   Correct Answer: C Explanation: The Ballast Cleaning Machine (BCM) is specifically designed for the deep screening and cleaning of the ballast bed.

4. The breathing length provided at each end of LWR is A) 50 m B) 100 m C) 250 m D) 500 m

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   Correct Answer: B Explanation: The breathing length is the portion of a Long Welded Rail (LWR) at each end that exhibits longitudinal movement due to temperature changes, typically 100 m.

5. Preventive grinding of rail is recommended after every A) 10 MGT B) 40–60 MGT C) 100 MGT D) 150 MGT

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   Correct Answer: B Explanation: To extend rail life and prevent surface defects, grinding is recommended once every 40–60 Million Gross Tonnes (MGT) of traffic.

6. The defect size above which a rail must be removed immediately as per USFD policy is A) 3% of head area B) 5% of head area C) 8% of head area D) 10% of head area

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   Correct Answer: C Explanation: According to USFD (Ultrasonic Flaw Detection) norms, a rail defect exceeding 8% of the head area requires immediate removal.

7. Q-value of track more than which limit is considered “Needs attention”? A) 20 B) 30 C) 40 D) 50

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   Correct Answer: C Explanation: A Q-value (Track Quality Index) exceeding 40 indicates that the track section requires maintenance attention.

8. Who is the overall in-charge of track maintenance for a section? A) Station Master B) PWI (Permanent Way Inspector) C) ADEN D) DEN

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   Correct Answer: B Explanation: The PWI (now often designated as SSE/P-Way) is the primary official responsible for the maintenance and safety of a specific track section.

9. The policy of converting entire BG network into LWR was adopted in the year A) 1975 B) 1983 C) 1990 D) 2000

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   Correct Answer: B Explanation: Indian Railways officially adopted the policy to convert the entire Broad Gauge network to Long Welded Rails in 1983.

10. The maximum cant deficiency permitted on BG with 60 kg 90 UTS rail is A) 50 mm B) 75 mm C) 100 mm D) 125 mm

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    Correct Answer: C Explanation: For 60 kg 90 UTS rail sections on BG, the maximum allowable cant deficiency is 100 mm.

11. Which of the following is NOT a cause of rail corrugation? A) High axle load B) Rail grinding C) Steady braking D) Poor lubrication

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    Correct Answer: B Explanation: Rail grinding is a solution/maintenance activity used to remove corrugation, not a cause of it.

12. The frequency of USFD testing for BG main line is A) 1 month B) 2 months C) 4 months D) 6 months

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    Correct Answer: C Explanation: The standard frequency for Ultrasonic Flaw Detection (USFD) testing on BG main lines is once every 4 months.

13. Dynamic Track Stabiliser (DTS) is used for A) Tamping B) Lining C) Consolidation D) Screening

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    Correct Answer: C Explanation: The DTS machine is used to provide rapid artificial consolidation of the ballast bed after tamping or deep screening.

14. The first Indian route to use 60 kg 90 UTS rail was A) Delhi–Mumbai B) Delhi–Howrah C) Mumbai–Chennai D) Delhi–Chennai

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    Correct Answer: B Explanation: The Delhi–Howrah route (specifically the Howrah–Rajdhani section) was the first to implement the 60 kg 90 UTS rail standard.

15. Which year saw the launch of Track Management System (TMS) on Indian Railways? A) 2016 B) 2018 C) 2020 D) 2022

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    Correct Answer: C Explanation: The comprehensive digital Track Management System (TMS) was launched across Indian Railways in 2020 to modernize maintenance logging.

16. The maximum vertical acceleration permitted by Oscillograph car for 160 km/h is A) 0.15 g B) 0.20 g C) 0.25 g D) 0.30 g

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    Correct Answer: A Explanation: For speeds up to 160 km/h, the maximum vertical acceleration is restricted to 0.15 g (roughly equivalent to 5 mm/sec).

17. T-49 policy 2023 makes it mandatory to machine-pack track up to how many metres from the tip of switch? A) 50 m B) 100 m C) 150 m D) 200 m

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    Correct Answer: D Explanation: Under the T-49 policy of 2023, machine packing must extend at least 200 metres from the tip of the switch for stability.

19. Quick-Fire Facts (Memory Hooks)

• 6-3 rule → Gauge tolerance (+6/-3 mm)
• 10-12-15 → Screening cycle in years (BG-MG-NG)
• 100 m → Breathing length
• 40-60 MGT → Grinding interval
• Q-40 → Attention limit
• 8% → USFD removal limit

19. Quick-Fire Facts (Memory Hooks)

• 6-3 rule → Gauge tolerance (+6/-3 mm)
• 10-12-15 → Screening cycle in years (BG-MG-NG)
• 100 m → Breathing length
• 40-60 MGT → Grinding interval
• Q-40 → Attention limit
• 8% → USFD removal limit

Revise the above figures & policies thoroughly; 3–4 direct questions appear every year from track maintenance in all RRB technical & non-technical exams.