What is WAP 7 locomotive ?
The WAP 7 (Wide/broad Gauge AC Electric Passenger, Class 7) is a three-phase AC electric passenger locomotive developed by the Chittaranjan Locomotive Works. It is the most powerful passenger locomotive in the Indian Railways' fleet. It is a passenger variant of the WAG 9 freight locomotive with a modified gear ratio to pull lighter loads at higher speeds. It is capable of hauling 24 coach trains at speeds ranging 110–140 km/h (68–87 mph), depending on the MPS (Maximum Permissible Speed) of the sector, and is now largely used by Northern Railways (NR), South Central Railway (SCR), Central Railways (CR), South East Central Railway Zone (SECR), South Eastern Railways (SER), West Central Railways (WCR), Eastern Railways (ER),...
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Western Railway zone (WR), North Central Railway zone (NCR), South Western Railway (SWR) etc among other zones. As of March 2020, there are 1024 locomotives in service, all of which are fitted with tightlock couplers (for central buffer coupling) and chain link couplers. In February 2017, Diesel Locomotive Works built their first WAP 7 class locomotive.[1]
Performance
With a maximum speed rating of 140 km/h (87 mph) the WAP-7 has the highest acceleration figures while hauling mail/express trains. The WAP-7 can also haul loads of 24-26 passenger coaches (1,430–1,550 t or 1,410–1,530 long tons or 1,580–1,710 short tons at 130 km/h or 81 mph). It is the most successful passenger locomotive on the Indian Railways roster after the WAP 4. It was initially used to haul premium train services like the Rajdhani Express, Shatabdi Express and the Duronto Express.[3] As more locomotives were rolled out, the WAP 7 became the official link of several state trains like the Telangana Express, Kerala Express, Paschim Express, Purushottam express, Vikramshila express, Poorva express,Karnataka express and among others. The locomotives have been used as a regular link for many of the Garib Rath express and many Humsafar expressservices and eventually extended to a significant number of AC Express and Mail/Superfast Express services like Jaipur Superfast Express, Thiruvananthapuram Mail, Mangalore Mail, Bangalore Mail, Sewagram express and so on. It is soon to be the most commonly used passenger locomotive. Upgrades are underway to increase power output and maximum speed. The First High Speed version WAP-7 HS loco ( loco no 30750) was launched on 28 February 2019 capable of attaining 160 km/h with overall reduction in weight by 14 tons.
30333 WAP-7 locomotive of RPM (Royapuram) shed at Mysuru, Karnataka.
The WAP-7 locomotive can deliver 6,125 hp (4,567 kW) continuously, with regenerative braking being one of its salient features. Regenerative braking is deployed on down gradients conserving energy to the tune of 30-35 percent. It has an inbuilt microprocessor based fault diagnostic system to make troubleshooting easier.[4]
Head-on Generation (HOG)
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.[5][6][7]
Technical Specifications
Technical Specifications[8] Manufacturers Chittaranjan Locomotive Works (CLW)
Diesel Locomotive Works (DLW)
Diesel Locomotive Modernisation Works
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.
Gear Ratio 72:20 , 70:22( for HS Version)
Axle load 20.5 t (20.2 long tons; 22.6 short tons)
Wheel diameter 1,092 mm (43 in) new, 1,016 mm (40 in) worn
Wheelbase 15,700 mm (51 ft 6 1⁄8 in)
Bogies Co-Co, Fabricated Flexicoil Mark IV bogies; bogie wheelbase 1,850 mm (72 7⁄8 in) + 1,850 mm (72 7⁄8 in)
Unsprung mass per axle 3.984 t (3.921 long tons; 4.392 short tons)
Length over buffers 20,562 mm (67 ft 5 1⁄2 in)
Length over headstocks 19,280 mm (63 ft 3 in)
Body width 3,152 mm (10 ft 4 1⁄8 in)
loco weight 123 t (121 long tons; 136 short tons)
Cab length 2,434 mm (95 7⁄8 in)
Pantograph locked down height 4,255 mm (13 ft 11 1⁄2 in)