Memu Units
MEMU Units – Mainline Electric Multiple Units for Indian Railways
1. What is a MEMU?
- MEMU = Mainline Electric Multiple Unit
- Designed for sub-urban & short-distance inter-city services (60–200 km)
- Self-propelled electric train-set (no separate locomotive)
- Faster acceleration & deceleration than conventional loco-hauled trains → reduces station dwell time
- Maximum commercial speed: 110 km/h (design) / 100 km/h (service)
- Formation: 4-car, 8-car, 12-car or 16-car modular rakes; can run in multiple-unit operation (up to 4 rakes = 24 coaches)
2. Technical Specifications
| Parameter | Value |
|---|---|
| Traction system | 25 kV 50 Hz AC overhead catenary |
| Power-on-wheels | 3-phase IGBT–VVVF inverter control |
| Traction motors | 3-phase asynchronous (induction) type, 250 kW per motor |
| Motor coaches (MC) | End cars with driving cab; 4 motors per MC |
| Trailer coaches (TC) | No motors; can be fitted with pantograph for auxiliary supply |
| Power rating (8-car) | 4 × 1 MW = 4 MW (≈ 5,400 hp) |
| Acceleration | 0.7 m/s² (loaded) |
| Braking | Regenerative + Electro-pneumatic friction + Parking brake |
| Regenerative energy | 25–30 % of total traction energy returned to grid |
| Coupler | Scharfenberg (automatic) – push-button coupling in 2 min |
| Passenger doors | 4 per side per coach, 1,300 mm wide, bi-parting sliding plug type |
| Seating | 2 × 2 reversible + standing room; crush load 150–160 passengers per coach |
| Material | Stainless-steel car shell, crash-worthy cab |
| Bogies | ICF-designed fabricated, 2.3 m wheel-base, air-spring secondary suspension |
| Track gauge | 1,676 mm (Indian Broad Gauge) |
| Axle load | 16.5 t (≤ 18 t after POH) |
| Minimum curve | 100 m (mainline), 80 m in yards under 5 km/h |
| Safety systems | Vigilance control device (VCD), ATP/TPWS compatible, fire detection in latest lots |
3. Historical Milestones
| Year | Event |
|---|---|
| 1994 | First 4-car MEMU conceived by ICF to replace conventional EMUs on mainline sections |
| 1995 | First 4-car prototype (speed 100 km/h) turned out by ICF; trials on SR & SCR |
| 2000 | RDSO finalises 8-car standard; production shift to ICF & RCF |
| 2004 | 12-car MEMU approved; first rake allotted to South Central Railway |
| 2009 | RDSO upgrades design to 110 km/h with new bogies & IGBT drives |
| 2014 | “Make in India” push – BEML & Alstom supply propulsion equipment; 1st stainless-steel 16-car rake for Howrah–Kharagpur |
| 2016 | 1,000th MEMU coach rolled out by ICF |
| 2018 | First 3-phase MEMU with regenerative braking flagged off by MR on Northern Railway |
| 2020 | 160 km/h MEMU Lite project cleared under “Mission Raftaar” (under development) |
| 2021 | 1,800 MEMU coaches in active inventory; 150 rakes (4/8/12/16-car) sanctioned in FY 21-22 |
| 2022 | Train-18 (Vande Bharat) philosophy extended to MEMU: ICF begins aluminium-body 130 km/h “MEMU 2.0” (prototype) |
| 2023 | EBA (E-battery auxiliary) MEMU trial by NR – battery for hotel load during power block |
4. Current Status & Recent Updates (2023–24)
- Total fleet on roll: ≈ 1,950 coaches forming 210 rakes (zones keep swapping coaches)
- Highest density: Northern Railway (43 rakes), South Central (38), Eastern (27)
- Average daily kilometre: 450 km/train (against 300 km of conventional EMU)
- Energy saving: 28 % thanks to regenerative braking; ₹ 120 cr saved in traction power in 2022-23
- New features in 2023-24 lots
– COVID retro-fit: Plasma air purification, nano-coating on grab-rails
– CCTV + PA + Passenger info system with GPS-based LED boards
– Head-generation plant 2 × 250 kVA for hotel load; redundancy for 25 kV failure
– Fire-retardant cables (EN 45545 HL-3) & smoke detectors in roof-mounted HVAC - Production target 2024–25: 450 MEMU coaches (ICF 300, RCF 150)
- Green certification: ICF MEMU shop is first Indian rail unit to get ISO 14064-1 for carbon neutrality
- Upcoming corridors identified for MEMU conversion:
– Lucknow–Sitapur–Mailani (NR)
– Visakhapatnam–Raipur–Durg (ECoR)
– Bengaluru–Dharmavaram (SWR) - MEMU Lite (160 km/h) design review completed by RDSO; prototype expected 2025
- Cab signalling integration: MEMU rakes being fitted with KAVACH (ERTMS L-1) on SCR & NR
5. Quick-Fire Data Points for Exams
- First zone to receive MEMU: South Central Railway (1996)
- First stainless-steel 16-car rake: Howrah–Kharagpur (SER)
- Heaviest MEMU: 16-car weighs 640 t, seats 2,560 passengers
- Smallest unit: 4-car; 160 t; 640 seats
- Production units: ICF (Chennai), RCF (Kapurthala)
- Propulsion suppliers: BHEL, BEML, Alstom, Medha, Titagarh Firema
- RDSO code: EMU-05 (MEMU), EMU-07 (MEMU-AC)
- Permitted OHE neutral section length: 60 m at 100 km/h (with power-off coasting)
- Scheduled maintenance:
– Trip shed (daily) 2 h
– IOH (Intermediate Overhaul) 18 months / 300,000 km
– POH (Periodic Overhaul) 6 years / 1.2 million km - Battery back-up: 110 V DC Ni-Cd, 2 × 120 Ah for emergency lights & brakes
- Pantograph: Stone-benefit single-arm type, 200 A continuous current
- Maximum gradient: 1 in 50 (2 %) with full load
6. Practice MCQs (Railway Exam Pattern)
Click to view 15+ MCQs with answers
Q1. What does MEMU stand for?
A) Metro Electric Multiple Unit
B) Mainline Electric Multiple Unit
C) Modified Electric Motor Unit
D) Main Electric Multiple Unit
Ans: B
Q2. The maximum design speed of present-day MEMU coaches is:
A) 90 km/h
B) 100 km/h
C) 110 km/h
D) 120 km/h
Ans: C
Q3. Which production unit rolled out the first MEMU prototype in 1995?
A) RCF
B) ICF
C) BEML
D) Alstom
Ans: B
Q4. Regenerative braking in MEMU saves approximately:
A) 5–10 % energy
B) 15–20 % energy
C) 25–30 % energy
D) 40–50 % energy
Ans: C
Q5. The traction system used by MEMU is:
A) 750 V DC third rail
B) 1.5 kV DC OHE
C) 25 kV 50 Hz AC OHE
D) 3 kV DC OHE
Ans: C
Q6. How many wide sliding plug doors are provided per side in one MEMU coach?
A) 2
B) 3
C) 4
D) 5
Ans: C
Q7. The motor coach of MEMU is equipped with:
A) 2 traction motors
B) 4 traction motors
C) 6 traction motors
D) 8 traction motors
Ans: B
Q8. The scheduled POH periodicity for a MEMU coach is:
A) 3 years
B) 4.5 years
C) 6 years
D) 9 years
Ans: C
Q9. Which of the following is NOT a feature of the latest MEMU rakes?
A) Stainless-steel shell
B) IGBT–VVVF drive
C) Bio-toilets
D) Battery back-up for traction
Ans: D
Q10. The automatic coupler used between MEMU coaches is:
A) AAR
B) Scharfenberg
C) Dellner
D) H-type
Ans: B
Q11. The highest number of MEMU rakes is presently homed at:
A) Southern Railway
B) Northern Railway
C) Western Railway
D) South East Central Railway
Ans: B
Q12. The axle load of MEMU coach is limited to:
A) 14.5 t
B) 16.5 t
C) 18.5 t
D) 20.0 t
Ans: B
Q13. Under Mission Raftaar, MEMU Lite is being developed for a maximum speed of:
A) 130 km/h
B) 140 km/h
C) 160 km/h
D) 180 km/h
Ans: C
Q14. The auxiliary power supply during OHE failure in new MEMU rakes is provided by:
A) 750 V battery
B) 110 V Ni-Cd battery
C) E-battery (Li-ion) bank & head-generation set
D) Diesel generator car
Ans: C
Q15. Which safety device is now being fitted on MEMU to comply with Kavach signalling?
A) Flasher light
B) TPWS/ATP onboard unit
C) Slip coach indicator
D) OHE temperature sensor
Ans: B
Q16. The first 16-car stainless-steel MEMU was allotted to which section?
A) Chennai–Gummidipundi
B) Howrah–Kharagpur
C) Delhi–Rohtak
D) Palwal–Mathura
Ans: B
Q17. MEMU rakes save traction energy mainly due to:
A) Lighter stainless-steel body
B) Regenerative braking
C) Higher gear ratio
D) Less number of wheels
Ans: B
BETA
