Indian locomotive class WAP-7

From Wikipedia, the free encyclopedia
(Redirected from WAP 7)

HWH WAP7 hauling 02302 NDLS-HWH Rajdhani Special.jpg
Howrah based WAP-7 numbered 30686
Type and origin
Power typeElectric
BuilderChittaranjan Locomotive Works,
Banaras Locomotive Works,
Patiala Locomotive Works
Build date1999 - present
Total produced1435 as of January 2023
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

27.5 t (27.1 long tons; 30.3 short tons)


25.08 t (24.68 long tons; 27.65 short tons)
Loco weight130 t (130 long tons; 140 short tons)
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 speed240 km/h (150 mph)
Power outputMax Power : 6,355 hp (4,739 kW)
Continuous : 6,350 hp (4,740 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
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) engine, 7th generation (7). They entered service in 2000. A total of 1436 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 one of 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 6,350 hp (4,740 kW), 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) etc among other zones. As of October 2021, all of which 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.[1]

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)[edit]

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.[2][3][4]

Locomotive sheds[edit]

Zone Name Shed Code Quantity Introduction
Central Railway Ajni AQ 66 9 2010
Kalyan KYN 75 3 2019
Eastern Railway Howrah HWH 86 2012
Sealdah SDAH 15 15 2020
East Central Railway Gomoh GMO 46 2000
Barauni BJU 5 2021
Samastipur SPJ (D) 39 2022
East Coast Railway Visakhapatnam VSKP 45 7 2016
Northern Railway Ghaziabad GZB 109 52 2000
Ludhiana LDH 20 5 2022
North Central Railway Kanpur CNB 78 2019
North Eastern Railway Gonda GD (D) 5 2021
Izzatnagar IZN(D) 1 2023
Southern Railway Erode ED 66 3 2017
Royapuram RPM 78 26 2011
South Central Railway Lallaguda LGD 77 44 2008
Vijayawada BZA 28 2021
South Eastern Railway Tatanagar TATA 41 2017
Bondamunda BNDM 17 2018
Santragachi SRC 40 2017
South East Central Railway Bhilai BIA 5 6 2012
South Western Railway Krishnarajapuram KJM (D) 23 2019
Western Railway Vadodara BRC 133 2016
West Central Railway Tughlakabad TKD 69 43 2013
Itarsi ET 55 2018
Total 1224 211
Total Locomotives Active as of January 2023[5] 1435

See also[edit]


  1. ^ "Brief History of DLW". Ministry of Railways, Government of India. Retrieved 30 December 2017.
  2. ^ "Train had WAP-7 engine, 'black box' may reveal cause". Zee News. 9 August 2010. Retrieved 25 August 2012.
  3. ^ "Recent Developments". Chittaranjan Loco works. Retrieved 25 August 2012.
  4. ^ "Development of Electric locomotive with Head On Generation (HOG) facility" (PDF). Indian Railways.
  5. ^ "e-Locos".

External links[edit]