Indian locomotive class WAP-7

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 1503 WAP-7 have been built, with more units being built at CLW, Banaras Locomotive Works (BLW) and Patiala Locomotive Works (PLW).

WAP-7
CLW made WAP-7 rest at CLW yard
Type and origin
Power typeElectric
BuilderChittaranjan Locomotive Works,
Banaras Locomotive Works,
Patiala Locomotive Works
Build date1999 - present
Total produced1503 as of October 2023
Specifications
Gauge5 ft 6 in (1,676 mm)
BogiesCo-Co, Fabricated Flexicoil Mark IV bogies; bogie wheelbase 1,850 mm (72+7⁄8 in) + 1,850 mm (72+7⁄8 in)
Wheel diameter1,092 mm (43 in) new, 1,016 mm (40 in) worn
Wheelbase15,700 mm (51 ft 6+1⁄8 in)
Length:
​
 • Over beams20,562 mm (67 ft 5+1⁄2 in)
Width3,152 mm (10 ft 4+1⁄8 in)
Height:
​
 • Pantograph4,255 mm (13 ft 11+1⁄2 in)
Axle loadWAP 7

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

WAP 7HS

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.
TransmissionElectric
Gear ratioWAP 7
72:20
WAP 7HS
70:22
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
Career
OperatorsIndian Railways
Numbers30201+ CLW

37001+ BLW

39000+ PLW
LocaleIndia
First run19 May 2000

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).

History

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) 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.[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)
HOG equipped 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
HOG Non HOG
Central RailwayAjniAQ 63 3 2010
Kalyan KYN 58 6 2019
Pune PA (D) 23 1 2023
Eastern RailwayHowrahHWH 84 2012
SealdahSDAH18 12 2020
East Central RailwayGomohGMO 46 2000
BarauniBJU5 2021
SamastipurSPJ (D) 39 2022
East Coast RailwayVisakhapatnamVSKP 46 6 2016
Northern RailwayGhaziabadGZB 112 43 2000
LudhianaLDH20 5 2022
North Central Railway Kanpur CNB 79 2019
North Eastern Railway Gonda GD (D) 17 2021
Izzatnagar IZN (D) 6 2023
North Western Railway Bhagat Ki Kothi BGKT (D) 16 2023
Southern RailwayErodeED 75 2017
RoyapuramRPM 96 13 2011
South Central RailwayLallagudaLGD 85 41 2008
Vijayawada BZA 28 2021
South Eastern Railway TatanagarTATA 43 2017
Bondamunda BNDM 16 2018
Santragachi SRC 40 2017
South East Central RailwayBhilaiBIA 7 4 2012
South Western RailwayKrishnarajapuramKJM (D) 26 2019
Western RailwayVadodaraBRC 149 2016
West Central RailwayTughlakabadTKD 80 22 2013
ItarsiET 68 2018
Total 1345 156
Total Locomotives Active as of October 2023[8] 1501
  • Howrah based WAP7 on lead with 02302 New Delhi - Howrah Rajdhani Express Special at Janai Road
    Howrah based WAP7 on lead with 02302 New Delhi - Howrah Rajdhani Express Special at Janai Road
  • LGD WAP-7 30306 at Bangalore
    LGD WAP-7 30306 at Bangalore
  • Vijayawada WAP-7 39155 with 12075 Kozhikode Main Thiruvananthapuram Central Jan Shatabdi Express Skipping Thuravoor Railway Station in Kerala.
    Vijayawada WAP-7 39155 with 12075 Kozhikode Main Thiruvananthapuram Central Jan Shatabdi Express Skipping Thuravoor Railway Station in Kerala.
  • New Delhi-Lucknow Tejas Express powered by WAP-7, standing at New Delhi.
    New Delhi-Lucknow Tejas Express powered by WAP-7, standing at New Delhi.
  • WAP-7 #30261 charging on time running 22416 NDLS-VSKP A.P. A.C. Express.
    WAP-7 #30261 charging on time running 22416 NDLS-VSKP A.P. A.C. Express.
  • A Ghaziabad based WAP-7 hauling the Bhubaneswar Rajdhani Express
  • WAP-7 with the Bangalore Rajdhani Express near Lingampally Railway Station
  • RPM based WAP-7
  • Jammu Tawi bound Humsafar Express leaving Kazipet Junction, hauled by VSKP WAP-7 No. 37062
    Jammu Tawi bound Humsafar Express leaving Kazipet Junction, hauled by VSKP WAP-7 No. 37062
  • 12737 Goutami Express at Moula-ali with a WAP-7 loco
    12737 Goutami Express at Moula-ali with a WAP-7 loco

See also

References
  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 Loco works. Retrieved 25 August 2012.
  7. "Development of Electric locomotive with Head On Generation (HOG) facility" (PDF). Indian Railways.
  8. "e-Locos".
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