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Indian locomotive class WAP-7

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CLW made WAP-7 at CLW yard.
Type and origin
Power typeElectric
BuilderChittaranjan Locomotive Works,
Banaras Locomotive Works,
Patiala Locomotive Works
Build date1999 - present
Total produced1705 as of July 2024
Gauge5 ft 6 in (1,676 mm)
BogiesCo-Co, Fabricated Flexicoil Mark IV bogies; bogie wheelbase 1,850 mm (72+78 in) + 1,850 mm (72+78 in)
Wheel diameter1,092 mm (43 in) new, 1,016 mm (40 in) worn
Wheelbase15,700 mm (51 ft 6+18 in)
 • Over beams20,562 mm (67 ft 5+12 in)
Width3,152 mm (10 ft 4+18 in)
 • Pantograph4,255 mm (13 ft 11+12 in)
Axle loadWAP 7

20.5 t (20.2 long tons; 22.6 short tons)[1]


18.08 t (17.79 long tons; 19.93 short tons)[2]
Loco weight123 t (121 long tons; 136 short tons)[3]
Power supply3-phase 2180 V 50 Hz
Electric system/s25 kV 50 Hz AC Overhead
Current pickup(s)Pantograph
Traction motors6FRA 6068 3-phase squirrel-cage induction motors
850 kW (1,140 hp), 2180 V, 1283/2484 rpm, 270/310A;
Weight-2,100 kg (4,600 lb), forced-air ventilation, axle-hung, nose-suspended;
Torque 6,330–7,140 N⋅m (4,670–5,270 lbf⋅ft)
~88% efficiency.
Gear ratioWAP 7
Loco brakeAir and regenerative
Train brakesAir
Performance figures
Maximum speed140 km/h (87 mph) (WAP-7)

160 km/h (99 mph) (WAP-7HS)
Potential speed: 180 km/h (110 mph) (WAP-7HS)

155 km/h (96 mph) (WAP-7)
Power outputMax Power : 6,350 hp (4,740 kW)
Continuous: 6,120 hp (4,563.68 kW)
Tractive effortStarting : 322.4 kN (72,500 lbf)
Continuous : 228 kN (51,000 lbf) at 71 km/h
OperatorsIndian Railways
Numbers30201+ CLW

37001+ BLW

39000+ PLW
LocaleAll over India
First run19 May 2000

The Indian locomotive class WAP-7 is a class of 25 kV AC electric locomotives that was developed in 1999 by Chittaranjan Locomotive Works (CLW) for Indian Railways. The model name stands for broad gauge (W), AC Current (A), Passenger traffic (P) locomotive, 7th generation (7). They entered service in 2000. A total of 1676 WAP-7 have been built, with more units being built at CLW, Banaras Locomotive Works (BLW) and Patiala Locomotive Works (PLW).

The WAP-7 is the most successful locomotives of Indian Railways serving passenger trains for over 23 years. It is a passenger variant of the WAG-9 freight locomotive with a modified gear ratio to pull lighter loads at higher speeds. With an output of 6125HP, it is the most powerful passenger locomotive in the Indian Railways fleet, and the most numerous passenger locomotive in India. The WAP-7 is capable of hauling 24 coach trains at speeds 110–140 km/h (68–87 mph).



It is now largely used by Northern Railways (NR), South Central Railways (SCR), Central Railways (CR), South East Central Railways (SECR), South Eastern Railways (SER), West Central Railways (WCR), Eastern Railways (ER), Western Railways (WR), North Central Railways (NCR), South Western Railways (SWR), Southern Railways (SR), East Central Railways (ECR), East Coast Railways (ECoR), North Eastern Railways (NER), North Western Railways (NWR), Northeast Frontier Railways (NFR) among other zones. As of October 2021, all of these are fitted with H-type transition couplers which are compatible with both screw coupling and centre-buffer coupling. In February 2017, Banaras Locomotive Works built their first WAP 7 class locomotive.[4]

In 2019, a variant of the WAP-7, designated the WAP-7HS, was introduced for higher speeds. The WAP-7HS has a max speed of 180 km/h (110 mph), and is capable of hauling a 24-car train at 160 km/h (99 mph) as opposed to the 140 km/h (87 mph) of the original. Indian Railways plans to use the WAP-7HS for Shatabdi, Rajdhani, and Duronto express trains. However, as of September 2022, it has not been confirmed if any others have been built, and the single completed WAP-7HS has stayed restricted to 130 km/h (81 mph).

Head-on Generation (HOG)

The HOG ports are equipped on right side upper and left side down on Erode based WAP-7 at White Field railway station

A main feature of Majority locomotives of this class is that they eliminate the need to have separate End on Generation (EOG) sets or DG (Diesel Generator) sets for supplying power to the train resulting in significant savings on maintenance and running costs. This technology, called HOG or "Head On Generation", transfers electric power from the loco's pantograph to the coaches instead of EOG where a power car equipped with diesel generator capable of generating adequate power of 3-phase 50 Hz 415 V / 750 V AC (called 'head-end power') is provided at either end of the train rake to supply power.[5][6][7]

Locomotive sheds

Zone Name Shed Code Quantity Introduction
Central Railway Ajni AQE 65 3 2010
Kalyan KYNE 69 6 2019
Pune PADX 34 1 2023
Eastern Railway Howrah HWHE 87 2012
Sealdah SDAD 20 10 2020
East Central Railway Gomoh GMOE 46 2000
Barauni BJUE 6 2021
Samastipur SPJD 46 2022
East Coast Railway Visakhapatnam WATE 64 5 2016
Northern Railway Ghaziabad GZBE 119 39 2000
Ludhiana LDHE 30 4 2022
North Central Railway Kanpur CNBE 84 2019
North Eastern Railway Gonda GDDX 17 2021
Izzatnagar IZND 6 2023
Gorakhpur GKPL 5 2024
Northeast Frontier Railway Siliguri SGUD 4 2024
North Western Railway Bhagat Ki Kothi BGKD 26 2023
Southern Railway Erode EDE 76 2017
Royapuram RPME 103 10 2011
South Central Railway Lallaguda LGDE 116 33 2008
Vijayawada BZAE 53 2021
South Eastern Railway Tatanagar TATE 58 2017
Bondamunda BNDL 16 2018
Santragachi SRCE 26 2017
South East Central Railway Bhilai BIAE 11 2 2012
South Western Railway Krishnarajapuram KJMD 57 2019
Hubli UBLD 6 2024
Western Railway Vadodara BRCE 150 2016
Valsad BLEE 20 2024
West Central Railway Tughlakabad TKDE 79 21 2013
Itarsi ETE 72 2018
Total 1572 133
Total Locomotives Active as of July 2024[8] 1705

See also



  1. ^ "[IRFCA] Indian Railways FAQ - AC Electric Locomotives".
  2. ^ "What are the specifications of WAP 7 HS?".
  3. ^ "[IRFCA] Indian Railways FAQ - AC Electric Locomotives".
  4. ^ "Brief History of DLW". Ministry of Railways, Government of India. Retrieved 30 December 2017.
  5. ^ "Train had WAP-7 engine, 'black box' may reveal cause". Zee News. 9 August 2010. Retrieved 25 August 2012.
  6. ^ "Recent Developments". Chittaranjan Locomotive Works. Retrieved 25 August 2012.
  7. ^ "Development of Electric locomotive with Head On Generation (HOG) facility" (PDF). Indian Railways.
  8. ^ "e-Locos".