Indian locomotive class WAP-7

WAP-7
Vishakhapatnam based WAP-7 hauling Tirupati-Jammu Tawi Humsafar Express near Kazipet
Type and origin Power type Electric Builder Chittaranjan Locomotive Works, Banaras Locomotive Works, Diesel-Loco Modernisation Works Build date 10 May 2000 - present Total produced 1422 as of January 2022
Specifications Gauge 5 ft 6 in (1,676 mm) Bogies Co-Co, Fabricated Flexicoil Mark IV bogies; bogie wheelbase 1,850 mm (72+7⁄8 in) + 1,850 mm (72+7⁄8 in) Wheel diameter 1,092 mm (43 in) new, 1,016 mm (40 in) worn Wheelbase 15,700 mm (51 ft 6+1⁄8 in) Length: ​  • Over beams 20,562 mm (67 ft 5+1⁄2 in) Width 3,152 mm (10 ft 4+1⁄8 in) Height: ​  • Pantograph 4,255 mm (13 ft 11+1⁄2 in) Axle load WAP 7 20.5 t (20.2 long tons; 22.6 short tons) WAP 7HS 18.08 t (17.79 long tons; 19.93 short tons) Loco weight 123 t (121 long tons; 136 short tons) Power supply 3-phase 2180 V 50 Hz Electric system/s 25 kV 50 Hz AC Overhead Current pickup(s) Pantograph Traction motors 6FRA 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. Transmission Electric Gear ratio WAP 7 72:20 WAP 7HS 70:22 Loco brake Air and regenerative Train brakes Air
Performance figures Maximum speed 180 km/h (110 mph) Power output Max Power : 6,350 hp (4,740 kW) Continuous : 6,120 hp (4,560 kW) Tractive effort Starting : 322.4 kN (72,500 lbf) Continuous : 228 kN (51,000 lbf) at 71 km/h
Career Operators Indian Railways Numbers 30201+ CLW 37001+ BLW 39000+ DLMW Locale India First run 19 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 1422 WAP-7 have been built, with more units being built at CLW, Banaras Locomotive Works (BLW) and Diesel-Loco Modernisation Works (DLMW).

The WAP-7 is one of the most successful locomotives of Indian Railways serving passenger trains for over 21 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, with a total 1422 locomotives built as of January 2022. 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) 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.

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 November 2021, 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)

File:HWH HOG WAP7.jpg

Howrah based "HOG" equipped WAP-7

A main feature of some 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.

Locomotive sheds

Zone	Name	Shed Code	Quantity	Introduction
Central Railway	Ajni	AQ	65	27 December 2010
	Kalyan	KYN	71	21 June 2019
Eastern Railway	Howrah	HWH	89	20 February 2012
	Sealdah	SDAH	30	01 April 2020
East Central Railway	Gomoh	GMO	57	19 May 2000
	Barauni	BJU	20	21 September 2021
East Coast Railway	Visakhapatnam	VSKP	49	22 November 2016
Northern Railway	Ghaziabad	GZB	164	19 May 2000
	Tughlakabad	TKD(D)	42	15 April 2021
North Central Railway	Kanpur	CNB	76	31 March 2019
North Eastern Railway	Gonda	GD(D)	17	27 February 2021
Southern Railway	Erode	ED	65	19 October 2017
	Royapuram	RPM	103	21 January 2011
South Central Railway	Lallaguda	LGD	130	26 December 2008
	Vijayawada	BZA	18	27 March 2021
South Eastern Railway	Tatanagar	TATA	27	18 April 2017
	Bondamunda	BNDM	15	31 August 2018
	Santragachi	SRC	54	9 November 2017
South East Central Railway	Bhilai	BIA	51	6 September 2012
South Western Railway	Krishnarajapuram	KJM(D)	23	31 Aug 2019
Western Railway	Vadodara	BRC	138	23 April 2016
West Central Railway	Tughlakabad	TKD	95	25 January 2013
	Itarsi	ET	23	1 December 2018
Total Locomotives Active as of 01-01-2022			1422

See also

• Indian Railways
• Locomotives of India
• Rail transport in India