Testing Equipment – Railway General Knowledge

1. Introduction

Railway testing equipment ensures safety, reliability and efficiency of rolling stock, track, signalling and electrical systems. Indian Railways (IR) follows RDSO/ICF/BIS/UIC/EN/ISO standards. Testing is done at three levels:

• Type (Design) Tests – on prototype
• Routine (Acceptance) Tests – on every unit
• Periodic (In-service) Tests – during maintenance

2. Classification of Railway Testing Equipment

3. Key Equipment in Detail

3.1 Ultrasonic Flaw Detector (USFD) – Track

• Purpose: Detect internal rail flaws (transverse, horizontal, bolt-hole).
• Technique: 0° & 70° probes, 4 MHz frequency, pulse-echo method.
• Spec: RDSO M&C/NDT/10/2004; sensitivity ≥ 2 mm FBH (Flat Bottom Hole).
• Recent: Indigenous “Rail-Saver” MK-IV (DRDO-IR) supplied 2023; GPS & cloud upload.

3.2 Track Recording Car (TRC)

• Measures geometry parameters: gauge (±0.5 mm), twist (base 3.6 m), alignment (±1 mm/10 m), top (±1 mm/10 m), cant deficiency.
• Speed: 160 kmph max (BG); 200 kmph on DFC (Wagon-TRC converted 2022).
• Sensors: Laser chord, accelerometer, gyroscope.
• Output: 3D track-geometry plot; alerts via T-369 software to track-machines.

3.3 Oscillograph Metro Coach (OMS)

• Introduced: 1962 Kolkata Metro; upgraded 2019 with MEMS-based 3-axis accelerometers.
• Use: Ride-index (RI) ≤ 2.75 (excellent) as per ISO 2631.

3.4 Wheel Impact Load Detector (WILD)

• Location: 88 installations (as on 1.4.2024) – 32 on DFC.
• Principle: Strain-gauge on rail web; measures vertical wheel-load > 90 kN (alarm) & > 110 kN (detain).
• Integration: RF-ID tag reading; auto SMS to ROH depot.

3.5 universal Testing Machine (UTM)

• Capacity: 1000 kN (electro-mechanical) at RDSO Lucknow.
• Tests: Tensile (UTS), Yield (0.2 % proof), % elongation, Bend (120°).
• Materials: IRS M-41 steel (350 MPa YS), IRS M-44 (540 MPa).

3.6 Spring Testing Machine

• Load range: 0–200 kN; deflection 0–150 mm.
• Acceptance criteria: Load loss ≤ 5 % after 3×10⁶ cycles (UIC 822).

3.7 Insulation & Hi-pot Tester

• OHE: 90 kV DC hi-pot for 1 min (new insulator string).
• Rolling stock: 4 kV AC, 1 min between windings & body (IRS S-23).

3.8 Earth Resistance Tester (Megger)

• Specification: ≤ 1 Ω for major stations, ≤ 2 Ω for minor stations (IS 3043).
• Method: Fall-of-potential (62 % rule).

3.9 Axle Counter Tester

• Count check: 0–9999; simulated wheel pass at 2 kHz.
• Safety: SIL-4 as per CENELEC 50129.

4. Historical Milestones

• 1926: First USFD trial on GIPR by Krautkramer.
• 1958: RDSO designs indigenous “Type-2” USFD; production at ICF.
• 1962: OMS commissioned for Kolkata Metro.
• 1987: TRC-1 built by BEML on YDM-4 under-frame; max 80 kmph.
• 1999: WILD prototype at Jhansi-North cabin.
• 2009: RDSO introduces digital USFD with A-scan & B-scan.
• 2014: TRC upgraded to 160 kmph with inertial referencing system (IRS).
• 2020: “Rail-Drishti” web-portal launched – live USFD & TRC data.
• 2023: First self-propelled 200 kmph TRC (SP-TRC-200) flagged off by MR.

5. Current Status & Recent Updates (2023-24)

• Mission 3000 T-18: 3000 km of track to be tested daily by TRC-18 coaches by 2025.
• AI-based USFD: Pilot on WCR; automatic classification of flaw severity.
• BEML order: 15 new USFD sets with Phased-Array (PAUT) capability (Feb 2024).
• DFCCIL: Deploying 24 WILD + 12 TRC for 3400 rkm DFC.
• Make-in-India: 85 % of testing equipment now procured through domestic vendors (RailTel, Medha, DEC).
• Green initiative: Battery-powered TRC-cum-RE (regenerative) saves 12 % traction energy.

6. Important Facts & Figures (Memory Bytes)

• RDSO: Established 1957, Lucknow; nodal agency for testing standards.
• Frequency used in USFD: 4 MHz (BG), 2 MHz (MG).
• Calibration block: V-2 (IS 6908) for rail; step wedge 1–10 mm.
• Record: Longest rail flaw – 450 mm transverse crack detected on 12-03-2022, ER.
• Penalty clause: Supplier pays 2 % extra if 1 % wagons fail static brake-test.
• Life of rail: 1000 GMT (Gross Million Tonnes) before scheduled USFD.
• Brake-power dyno: Absorbs 3000 kW (WAP-7 loco) at 120 kmph.
• Digital TRC sampling: 0.25 m (every) at 160 kmph → 640 Hz.
• Rail temperature expansion: 1 °C rise → 1.15 mm per 30 m rail → tested in climate chamber −10 °C to 70 °C.

7. 15+ MCQs with Answers

1. The frequency most commonly used in Indian Railways USFD for BG track is A) 2 MHz B) 4 MHz C) 5 MHz D) 10 MHz

   Show Answer

   Correct Answer: B Explanation: A frequency of 4 MHz is the standard used for Ultrasonic Flaw Detection (USFD) of rails on Indian Railways to balance penetration and resolution.

2. The maximum permissible vertical impact load for a freight wheel to be detained by WILD is A) > 90 kN B) > 100 kN C) > 110 kN D) > 120 kN

   Show Answer

   Correct Answer: C Explanation: Wheel Impact Load Detectors (WILD) flag freight wheels for immediate attention or detention if the impact load exceeds 110 kN.

3. Which RDSO specification governs the digital ultrasonic flaw detector used on IR? A) M&C/NDT/05/2000 B) M&C/NDT/10/2004 C) IRS:T-12/2009 D) RDSO/SPN/144

   Show Answer

   Correct Answer: B Explanation: Digital USFD testing equipment on Indian Railways must comply with the RDSO specification M&C/NDT/10/2004.

4. The first Track Recording Car in India was commissioned in the year A) 1965 B) 1972 C) 1980 D) 1987

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   Correct Answer: D Explanation: The first dedicated Track Recording Car (TRC) was introduced into service on Indian Railways in 1987.

5. Ride Index (RI) value of 2.75 measured by OMS is classified as A) Excellent B) Good C) Satisfactory D) Uncomfortable

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   Correct Answer: A Explanation: A Ride Index (RI) value below 3.0, specifically around 2.75, is categorized as “Excellent” ride quality.

6. The insulation resistance test voltage for new OHE insulator string is A) 11 kV DC B) 25 kV AC C) 90 kV DC for 1 min D) 100 kV AC

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   Correct Answer: C Explanation: For new OHE (Overhead Equipment) insulators, a test voltage of 90 kV DC is applied for one minute to ensure dielectric strength.

7. The calibration block used for rail USFD is designated as A) V-1 block B) V-2 block (IS 6908) C) IIW block D) Step wedge block

   Show Answer

   Correct Answer: B Explanation: The V-2 calibration block, as per IS 6908 standards, is the standard reference used for calibrating rail USFD machines.

8. As per IS 3043, the maximum allowable earth resistance for major railway stations is A) 1 Ω B) 2 Ω C) 5 Ω D) 10 Ω

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   Correct Answer: A Explanation: To ensure safety and proper functioning of electrical systems, major stations must maintain an earth resistance of 1 Ohm or less.

9. Which of the following is NOT measured by Track Recording Car? A) Alignment B) Gauge C) Cross-level D) Wheel impact load

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   Correct Answer: D Explanation: Track Recording Cars measure track geometry (Alignment, Gauge, Twist, etc.); Wheel Impact Loads are measured by WILD sensors installed on the track.

10. The capacity of UTM (Universal Testing Machine) available at RDSO Lucknow is A) 100 kN B) 500 kN C) 1000 kN D) 2000 kN

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    Correct Answer: C Explanation: The heavy-duty UTM at RDSO Lucknow, used for testing rail and component strength, has a capacity of 1000 kN.

11. The method adopted for earth resistance measurement is A) Bridge method B) Fall-of-potential C) Direct current method D) Resonance method

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    Correct Answer: B Explanation: The “Fall-of-potential” method is the standard technical procedure for measuring the resistance of an earthing system.

12. The first metro in India to use OMS (Oscillation Monitoring System) was A) Delhi Metro B) Mumbai Metro C) Kolkata Metro D) Bangalore Metro

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    Correct Answer: C Explanation: Kolkata Metro was the first metro system in India to adopt OMS for monitoring ride quality and track-vehicle interaction.

13. How many Wheel Impact Load Detectors (WILD) are installed on Indian Railways as on 1.4.2024? A) 50 B) 72 C) 88 D) 120

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    Correct Answer: C Explanation: As of April 2024, Indian Railways has operationalized 88 WILD systems across various strategic locations on the network.

14. The digital TRC samples track geometry at every A) 0.10 m interval B) 0.25 m interval C) 0.50 m interval D) 1.00 m interval

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    Correct Answer: B Explanation: Modern digital Track Recording Cars sample and record geometry data at high resolution, typically every 0.25 metres.

15. Mission 3000 T-18 aims to test how many kilometres of track per day by 2025? A) 1000 km B) 2000 km C) 3000 km D) 5000 km

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    Correct Answer: C Explanation: The “Mission 3000” initiative targets the inspection and testing of 3000 km of track daily using high-speed recording systems.

16. The safety integrity level (SIL) for an axle counter tester should be A) SIL-1 B) SIL-2 C) SIL-3 D) SIL-4

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    Correct Answer: D Explanation: Because axle counters are vital for train detection and safety, their testing equipment must comply with the highest safety standard, SIL-4.

17. Which of the following is used to simulate wheel pass for axle counter testing? A) 50 Hz transformer B) 2 kHz frequency generator C) Magnetic shunt D) Infrared sensor

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    Correct Answer: B Explanation: A 2 kHz frequency generator is used during testing to simulate the electronic signal produced by a wheel passing over the axle counter sensor.

Last Updated: January 2026