Indian locomotive class WAG-7

Indian Railway freight class electric locomotive From Wikipedia, the free encyclopedia

The Indian locomotive class WAG-7 is a class of 25 kV AC electric locomotives that was developed in 1990 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), alternating current (A), goods traffic (G) engine, 7th generation (7). They entered service in 1992. A total of 1974 WAG-7 were built at CLW and BHEL between 1990 and 2015 by CLW and 2009 and 2023 by BHEL which made them the most numerous class of mainline electric locomotive till its successor the WAG-9.

Power typeElectric
Power typeElectric
Build date1990–2015(CLW)
2009–2023(BHEL)
Quick facts WAG-7, Type and origin ...
WAG-7
Arakkonam based WAG-7H at Ernakulam.
Type and origin
Power typeElectric
BuilderChittaranjan Locomotive Works (CLW),
Bharat Heavy Electricals Limited (BHEL).
Build date1990–2015(CLW)
2009–2023(BHEL)
Total produced1773 (CLW)
201 (BHEL)
1974
Specifications
Configuration:
  UICCo′Co′
Gauge5 ft 6 in (1,676 mm)
BogiesALCO Fabricated
Wheel diameterNew:1,092 mm (3 ft 7 in),
Half worn:1,055 mm (3 ft 5+12 in) and
Full worn:1,016 mm (3 ft 4 in)
Wheelbase3.8 m (12 ft 5+58 in)
Length20.934 m (68 ft 8+18 in)
Width3.179 m (10 ft 5+18 in)
HeightWAG-7 : 4.185 m (13 ft 8+34 in)[1]
WAG-7H : 4.135 m (13 ft 6+34 in)[2]
Axle loadWAG-7 : 20.5 tonnes (20.2 long tons; 22.6 short tons)
WAG-7H : 22 tonnes (22 long tons; 24 short tons)
Loco weightWAG-7 : 123 tonnes (121 long tons; 136 short tons)
WAG-7H : 132 tonnes (130 long tons; 146 short tons)
Electric system/s25 kV 50 Hz AC Overhead
Current pickuppantograph
Traction motorsWAG-7 : Hitachi HS15250A
WAG-7H : Hitachi HS15250G
MU working4
Loco brakeAir, Hand and Rheostatic (Friction)
Train brakesAir, Vacuum and Dual
Safety systemsSlip control, Main overload relay, Over voltage relay, No volt relay, Earth fault relay, Low pressure governor, Vacuum Control Governor, Train parting alarms and Brake cylinder cutoff valve
Performance figures
Maximum speed105 km/h (65 mph)
Power outputMax : 5,350 hp (3,990 kW)
Continuous : 5,000 hp (3,730 kW)
Tractive effortWAG-7 starting : 48 tons
WAG-7 continuous : 45 tons?
WAG-7H starting : 91 tons?
Factor of adh.0.345
Career
OperatorsIndian Railways
NumbersWAG-7 : 27001-27999, 28000-28770, 24501-24701
WAG-7H : 28024 and 28739
NicknamesSHANTIDAN, EKTA, KARAMVIR, GAJRAJ, SWARNABHA, SARVOTTAM, SAMARPAN, CAUVERY, SAMRAT, PRAYAS & AGRASAR
LocaleAll over India
Dispositionactive
Close

The WAG-7 is one of the most successful locomotives of Indian Railways,[peacock prose] serving freight trains since its introduction in 1990. Even though with the advent of new 3-phase locomotives like WAG-9 and WAG-12, all WAG-7 locomotives except ones destroyed in accidents, are in service and doing all types of duties.

History

The history of WAG-7 begins in the early 1990s with the aim of addressing the shortcomings of the previous WAG-5 class and remove steam locomotives from IR by a target date of 1990.[3] The WAG-5 though were great successes, had become underpowered to meet the growing demands of the Indian Railways. So in early 1990s IR decided to look for a successor the WAG-5 class. The required specification was of a 5000 horsepower locomotive.

Initially, the Indian railways invited tenders to build locomotives to the new specification. The following responses were received:

  • CLW submitted their upgraded WAG-5 model with 5000 hp with Co-Co bogies.
  • BHEL submitted a 5000 hp locomotive with thyristors control and Co-Co bogies.

Each company submitted their prototypes and Indian Railways designated these prototypes as the WAG-7 class and WAG-8 class respectively.[4] Technologically thyristor controlled BHEL WAG-8 was meant to be superior to the WAG-7 which was effectively using tap-changer technology from the 1960s. But due to issues from WAG-8, WAG-7 was selected for mass production.

However, even before the WAG-7 another type of electric locomotive was imported from ASEA in 1988. This locomotive was classified as WAG-6A. However WAG-6As were not selected for mass production because emergence of 3 Phase AC locomotives.[5]

Locomotive sheds

• Key : M -> WAG-7M (AC/AC loco, converted from DC/AC WCAM-3 loco)


Conversion of WCAM-3 to WAG-7M

Between 2022 and 2024, 46 WCAM-3 locomotives were converted to WAG-7M, while the remaining locomotives are used for passenger duties. For the conversion, these locomotives had their gear ratios changed from 18:64 to 16:65.

See also

References

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