Railway Locomotives
Railway Locomotives
Overview
Indian Railways uses three prime classes of locomotives – Electric, Diesel & Steam – built at CLW (Chittaranjan), DLW/DMW (Varanasi/Patiala) and preserved at heritage sheds. Post-2020, the national transporter has switched to 100 % electric traction on BG routes as part of Mission Net-Zero.
Key Facts & Figures
| Fact | Detail |
|---|---|
| 1. First steam loco in India | “Thomason” (0-4-0 tank) – 1852, built by R&WD for GIPR |
| 2. First electric loco | “Sir Leslie Wilson” (1500 V DC) – 1925, CSTM-Pune |
| 3. First diesel loco | WDM-1 #17000 – 1957, ALCo design, DLW |
| 4. First indigenous steam loco | “FA/0” – 1950, CLW |
| 5. First indigenous electric loco | WAG-1 #20701 – 1961, CLW |
| 6. First indigenous diesel loco | WDM-2 #18001 – 1964, DLW |
| 7. Heaviest freight loco | WAG-12B (12,000 HP, 133 t) – Made in India |
| 8. Fastest homologated loco | WAP-7 (180 km/h certified, 6,350 HP) |
| 9. Only 3-phase freight loco till 2020 | WAG-9 (6,120 HP, Siemens tech) |
| 10. Only 3-phase passenger loco till 2020 | WAP-5 (6,000 HP, ABB tech) |
| 11. Dual-cab freight loco family | WAG-11 (6,000 HP, 25 kV) |
| 12. First bio-toilet fitted loco | WDP-4D #40145 – 2016, DMW Patiala |
| 13. First HHP loco with IGBT | WAP-5 #30086 – 2003, CLW |
| 14. Heaviest steam loco | XA-class 2-8-2, 144 t working order |
| 15. Heritage joy-train steam loco | “Victoria” (0-6-0 WT) – Nilgiri Mountain Railway |
| 16. Only rack-rail steam section | Nilgiri (gradient 1 in 12.5) |
| 17. Last regular steam run | 1998 (Jalandhar-Firozpur) |
| 18. Total electric locos (Apr 2025) | >14,500 (BG) |
| 19. Total diesel locos (Apr 2025) | ~5,200 (BG + 2’-0” NG) |
| 20. Mission Net-Zero target | 2030 – complete electrification of BG network |
Important Points
- Classification Code: 1st letter – W (broad-gauge); 2nd letter – motive power (D-diesel, A-AC electric, M-mixed); 3rd letter – duty (P-passenger, G-goods, M-mixed).
- Horse-power brackets: WAP-5/7 (6,000–6,350), WAG-9/11/12 (6,120–12,000), WDP-4D (4,500), WDG-4/5 (4,000–5,500).
- **CLW (Chittaranjan) renamed CLW → CLW (Chittaranjan Locomotive Works) in 1950; DLW (Diesel Locomotive Works, Varanasi) merged with CLW in 2021 to form CLW (Indian Railways Locomotive Works).
- Regenerative braking is standard on 3-phase locos (WAP-5/7, WAG-9/11/12) saving ~35 % traction energy.
- HOG (Head-On-Generation): WAP-7 & WAG-9 supply 750 V 3-phase to coaches – eliminates power cars.
- Dual-mode loco “DW” class (25 kV AC + diesel) under development at DMW for Katra-Banihal section.
- LHB-certified locos: WAP-7, WDP-4D, WDG-4D – permitted to haul 160 km/h LHB rakes.
- Bio-diesel blend (B-5) trial done on WDG-4 locos in 2022.
- Remote monitoring: 100 % electric locos fitted with SIMRAN (GPS-based) for real-time tracking.
- Crew-friendly features: Air-conditioned cab, ergonomically redesigned on WAG-12B & WAP-7HS.
- Export: India gifted WDM-3A to Bangladesh & exported WAP-7 to Mozambique (2023).
- Steam heritage: 10 working steam locos maintained by IRCTC for tourism (Rajasthan, Tamil Nadu, Maharashtra).
- All-electric future: No new diesel loco sanctioned after 2018-19; DLW converted to produce electric locos only.
- Energy-efficiency record: WAG-12B achieved 98 % transformer efficiency – best among world freight locos.
- Tallest loco shed: Bondamunda (SER) – holds 250+ electric locos.
Frequently Asked in Exams
- Which is the first 12,000 HP electric loco of Indian Railways?
- What does “WAP-7” signify in loco classification?
- Where is the Nilgiri Mountain Rack-Rail steam section located?
- Name the only Indian production unit that makes WAG-12B.
- What is the purpose of HOG technology introduced on WAP-7?
Practice MCQs
Question:01 The first electric locomotive of Indian Railways was commissioned in
A) 1920
B) 1925
C) 1930
D) 1935
Show Answer
Correct Answer: B
Explanation: Indian Railways introduced its first electric locomotive in 1925 on the 1500 V DC suburban section of the Great Indian Peninsula Railway between Bombay VT and Kurla.
Question:02 WAG-12B locomotives are manufactured at
A) CLW, Varanasi
B) BHEL, Bhopal
C) CLW, Madhepura
D) DMW, Patiala
Show Answer
Correct Answer: C
Explanation: WAG-12B freight locomotives are produced by the Indian Railways–Alstom joint venture at the CLW facility in Madhepura, Bihar.
Question:03 Which of the following is a 100 % indigenous diesel locomotive class?
A) WDG-4
B) WDP-4D
C) WDG-5 (5500 HP)
D) WAG-12
Show Answer
Correct Answer: C
Explanation: WDG-5 (5500 HP) is India’s first completely indigenous high-horsepower diesel-electric freight locomotive, designed and built by Banaras Locomotive Works (BLW) without any foreign technology transfer.
Question:04 Regenerative braking is a standard feature of
A) Diesel shunters
B) Steam turbine locos
C) 3-phase electric locos
D) Mechanical rack locos
Show Answer
Correct Answer: C
Explanation: 3-phase electric locomotives use regenerative braking by converting the traction motors into generators, feeding the recovered energy back to the overhead supply.
Question:05 The steepest gradient (1 in 12.5) worked by steam locomotives is on
A) Darjeeling Himalayan Railway
B) Kalka-Shimla Railway
C) Nilgiri Mountain Railway
D) Matheran Hill Railway
Show Answer
Correct Answer: C
Explanation: The Nilgiri Mountain Railway, part of the Southern Railway zone, features the steepest gradient of 1 in 12.5 that is regularly worked by steam locomotives.
Question:06 What is the horse-power rating of the WAP-7 passenger locomotive?
A) 5,350 HP
B) 6,000 HP
C) 6,350 HP
D) 7,000 HP
Show Answer
Correct Answer: C
Explanation: The WAP-7 electric passenger locomotive is rated at 6,350 HP, making it one of the most powerful passenger locos in Indian Railways’ fleet.
Question:07 Which of the following was India’s first high-horsepower locomotive to adopt IGBT-based propulsion technology?
A) WAP-4
B) WAP-5
C) WAP-7
D) WAG-9
Show Answer
Correct Answer: B
Explanation: WAP-5, introduced in 1995, was the first Indian HHP (High Horse-Power) electric locomotive to use IGBT (Insulated-Gate Bipolar Transistor) converters for traction control, marking a technological leap over the older thyristor-based systems.
Question:08 Mission Net-Zero aims to electrify the entire BG network by
A) 2025
B) 2027
C) 2030
D) 2035
Show Answer
Correct Answer: C
Explanation: Indian Railways’ Mission Net-Zero targets 100 % electrification of the Broad-Gauge network by the year 2030 to cut carbon emissions and achieve net-zero by 2030.
Question:09 The only dual-cab freight electric loco class is
A) WAG-7
B) WAG-9
C) WAG-11
D) WAG-12
Show Answer
Correct Answer: CExplanation: WAG-11 is the only freight-dedicated electric locomotive in India equipped with dual cabs, allowing operation from either end without turning the loco.
Question:10 The heaviest freight steam locomotive class used in India was
A) WG-class 2-8-2
B) WP-class 4-6-2
C) XA-class 2-8-2
D) YP-class 2-6-2
Show Answer
Correct Answer: C
Explanation: The XA-class 2-8-2 was the heaviest freight steam locomotive class ever deployed on Indian Railways, built to haul heavy mineral loads.
BETA
