EMU & DEMU Train Sets
What are EMU & DEMU?
- EMU: Electric Multiple Unit – self-propelled electric coaches that draw power from 25 kV AC OHE.
- DEMU: Diesel Electric Multiple Unit – self-propelled diesel-powered coaches with on-board generator-battery set feeding traction motors.
1. Technical Information
| Parameter | EMU | DEMU |
|---|---|---|
| Traction system | 25 kV, 50 Hz AC OHE | 750 V DC on-board generator |
| Power car engine (DEMU) | 2 × 750 hp Cummins QSK-19 R-diesel | — |
| Transmission | 3-phase IGBT-VVVF inverter control | Same |
| Max. speed (service / design) | 100 / 130 kmph | 100 / 110 kmph |
| Acceleration | 0.5 m/s² (empty) | 0.45 m/s² |
| Deceleration | 0.8 m/s² (service brake) | 0.75 m/s² |
| Coach material | Stainless steel, 19 m long | Stainless steel, 19 m long |
| Axle load | ≤ 16 t | ≤ 16 t |
| Traction motor rating | 240 kW (3-phase squirrel-cage) | 200 kW |
| Coupler | Schoenberg C-Alpha tight-lock | Same |
| Brakes | Regenerative + electro-pneumatic disc & tread | Same |
| Train lighting | 110 V DC LED | 110 V DC LED |
| Passenger capacity (9-car EMU) | 6,100 (total) / 1,100 (seated) | 3,200 (4-car DEMU) |
| Formation code | DTC-MC-TC-MC-TC-MC-DTC | DPC-TC-MC-DTC |
Key sub-systems: Microprocessor-based train control & diagnostics (TCMS), roof-mounted lightweight transformer (EMU), fire detection & suppression, GPS-based PIS, bio-vacuum toilets, CCTV, automatic plug doors (new EMU), head-generation power (HOG) compatible.
2. Facts & Figures
- Indian Railways owns 12,000+ EMU coaches (2023) – largest suburban fleet in Asia.
- First EMU service: 3 Feb 1925, Bombay VT – Bori Bundi (DC 1.5 kV).
- First 25 kV AC EMU: 1964 Kolkata.
- First DEMU: 2003, Rewari – Ringas (NR).
- Energy regeneration: 35 % traction energy saved with regenerative braking.
- Cost: ₹6 crore per EMU coach, ₹11 crore per DEMU power car.
- Make-in-India: 100 % indigenous by ICF, Chennai; BEML & Rail Vikas Nigam.
- Longest DEMU run: 224 km, Banihal – Baramulla (J&K).
- Highest speed trial: 180 kmph with Medha 9-car EMU (2021, GZB).
- Head-On-Generation (HOG): Removes end-on-generator car; feeds hotel load directly from OHE – saves 4 lakh litres diesel/yr per 12-car rake.
- Battery-EMU: 2020 – ICF built 2 units capable of 15 km on battery.
- Vande Bharatani EMU: 2025 target – 200 semi-high-speed EMU rakes with 160 kmph.
3. Historical Developments
| Year | Milestone |
|---|---|
| 1925 | First DC EMU, Great Indian Peninsula Railway. |
| 1957 | Decision to adopt 25 kV AC traction; 1.5 kV DC phased out. |
| 1964 | First 25 kV AC EMU, Sealdah division. |
| 1996 | Medha consortium (BHEL, ABB) starts 3-phase drive. |
| 2001 | ICF designs stainless-steel 9-car EMU. |
| 2003 | Flag-off of first DEMU by Rail Minister Nitish Kumar. |
| 2012 | Launch of 12-car stainless-steel EMU with IGBT propulsion. |
| 2015 | First 15-car EMU, Mumbai CR. |
| 2016 | Indian Railways approves HOG conversion; removes SLR-cum-generator car. |
| 2018 | 160 kmph aluminium-body “Train-18” (later Vande Bharat) – EMU derivative. |
| 2020 | Battery-EMU prototype; 1st indigenised IGBT propulsion by Medha. |
| 2022 | 200th DEMU built by ICF; 100 % LED lighting & CCTV. |
| 2023 | 12-car MEMU with sealed gangways & aerodynamic driver cab. |
4. Current Status & Recent Updates (2023-24)
- 100 % HOG-enabled EMU rakes on WR & CR – eliminated 25 lakh litres diesel/yr.
- Phase-out of 1.5 kV DC completed in Mumbai (16 April 2023).
- Surge in DEMU demand: 300 additional DEMUs sanctioned for NE & hilly sections.
- Conversion of 8-car to 12-car in Bengaluru & Hyderabad to beat crowding.
- Battery-EMU trials successful in Mumbai 4th line – saves 30 % energy.
- Vande Bharatani EMU tender floated for 200 rakes (160 kmph) under PM-Gati Shakti.
- Indigenous IGBT modules (SCL, Medha) certified – cuts import bill by 18 %.
- Bio-vacuum toilets now standard fitment in all new EMU/DEMU coaches.
- LED destination boards & PIS in bilingual format for 700 stations.
- CCTV & facial recognition under Nirbhaya fund in 3,000 EMU coaches.
5. 15+ Model MCQs
1. Which voltage system is used for EMU trains in India?
25 kV, 50 Hz AC overhead equipment (OHE). Answer: 25 kV AC
2. The first EMU service in India ran between which stations?
Bombay VT – Bori Bundi. Answer: Bombay VT – Bori Bundi
3. What is the maximum service speed of a conventional 9-car EMU?
100 kmph. Answer: 100 kmph
4. Which organisation manufactures EMU/DEMUs for Indian Railways?
Integral Coach Factory (ICF), Chennai. Answer: ICF
5. The diesel engine used in a DEMU power car is of:
2 × 750 hp Cummins. Answer: 750 hp
6. Regenerative braking in EMU can save up to how much traction energy?
35 %. Answer: 35 %
7. Head-On-Generation (HOG) eliminates which coach?
End-on-generator (SLR) car. Answer: Generator car
8. The stainless-steel EMU coach length is:
19 m. Answer: 19 m
9. Which braking combination is provided in modern EMUs?
Regenerative + electro-pneumatic disc & tread. Answer: Regenerative + EP
10. First DEMU was flagged off in which year?
2003. Answer: 2003
11. Battery-EMU can run on battery for approximately:
15 km. Answer: 15 km
12. Which type of coupler is used in EMU rakes?
Schoenberg C-Alpha tight-lock. Answer: C-Alpha
13. 100 % conversion of Mumbai’s DC traction to AC was completed in:
April 2023. Answer: April 2023
14. Train-18, later named Vande Bharat, is based on which concept?
Electric Multiple Unit (EMU). Answer: EMU
15. The axle load of an EMU coach is limited to:
16 t. Answer: 16 t
16. Which division first received 25 kV AC EMUs in India?
Sealdah (ER). Answer: Sealdah
17. Energy-efficient LED lighting is provided in what percentage of EMU coaches?
100 %. Answer: 100 %
18. The traction motor rating in a 3-phase EMU is:
240 kW. Answer: 240 kW
BETA
