Indian locomotive class WAG-7

The Indian locomotive class WAG-7 is a class of 25 kV AC electric locomotives that was developed in the 1990 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), AC Current (A), Goods traffic (G) engine, 7th generation (7). They entered service in 1992. A total of 1970 WAG-7 were built at CLW and BHEL between 1990 to 2015, which made them the most numerous class of mainline electric locomotive till its successor the WAG-9.

WAG 7 / 7H
MGS WAG-7 running light towards Gurpa
Type and origin
Power typeElectric
BuilderWAG-7 and WAG-7H : Chittaranjan Locomotive Works(CLW)
WAG-7 : Bharat Heavy Electricals Limited(BHEL).
Total producedWAG-7/H: 1970
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 1⁄2 in) and
Full worn:1,016 mm (3 ft 4 in)
Wheelbase3.8 m (12 ft 5 5⁄8 in)
Length20.934 m (68 ft 8 1⁄8 in)
Width3.179 m (10 ft 5 1⁄8 in)
HeightWAG-7 : 4.185 m (13 ft 8 3⁄4 in)[1]
WAG-7H : 4.135 m (13 ft 6 3⁄4 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 pickup(s)pantograph
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 speedWAG-7 and WAG-7H
Design: 120 km/h (75 mph)
WAG-7H
Actual: 120 km/h (75 mph)
Certified: 110 km/h (68 mph)
Power outputMax : 5,500 hp (4,100 kW)
Continuous : 5,040 hp (3,760 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, 24501-24700
WAG-7H : 28024 and 28739
NicknamesSHANTIDAN, EKTA, KARAMVIR, GAJRAJ, SWARNABHA, SARVOTTAM, SAMARPAN, CAUVERY, SAMRAT, PRAYAS & AGRASAR
LocaleAll over India
Dispositionactive

The WAG-7 is one of the most successful locomotives of Indian Railways currently serving both freight and passenger trains for over 28 years. Even though with advent of new 3-phase locomotives like WAG-9 and WAG-12, all WAG-7 locomotives except one destroyed in accidents, rest are in service and doing all types of duties.

History

The history of WAG-7 begins in 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 became 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 5000hp 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]

Production History

On 3 August 1992, the first WAG-7 locomotive was inaugurated and christened by Mother Teresa as "SHANTIDAN". After undergoing trials the first 71 of this class were homed at Mughalsarai (MGS) shed and latter ones at Kanpur (CNB). Some units are retrofitted with Static Converters(STC) instead of Arno Rotary Converters. STCs are more efficient and require less maintenance. Also, STCs have self diagnostics making troubleshooting easier. WAG-7H is a heavy variant of WAG-7. WAG-7H #28739 has thicker under-frames. WAG-7 #27445 has closed-circuit cameras to monitor the pantograph along with a spotlight to illuminate the same at night, green lamps to exchange signals and a single windscreen on either side. New Katni (NKJ) shed has added Overhead Equipment(OHE) monitors. Some WAG-7 units have A.C. cabs, SIV, MPFDCS, MPCS, Single arm pantograph, FDCS, Additional COC, Rear-view mirrors, STS, Daulat Ram's Roof-mounted DBRs, SI, Modified ceilings, Bucket seats, Waist-level headlamps, High-reach pantographs, Vigilance Control Device(VCD), Wireless Multiple Control, Vertical Dynamic Brake Resistor(DBR) and microprocessor control. Some units have their MU cables removed. One unit has SCHUNK pantograph. Some units are assembled at Dahod Workshops. Initially WAG-7 had the body-shell similar to WAG-5 but later on all WAG-7 are/were fitted with crew safe shell like the WAP-4 since this provided more space and relatively safer during the impact on a head-on collision. WAG-7H have crew safe shell since beginning. Older WAG-7s have Tiger Face liveries (Red/Dark Blue on white) but newer WAG-7s by CLW have yellow stripe on blue livery. All BHEL built WAG-7s have Tiger Face livery. Now, even some older WAG-7s are repainted with yellow stripe on blue livery. It is also the most powerful indigenously designed freight-dedicated locomotive in India.

Technical Specifications

Instead of the ALCO asymmetric trimount Co-Co bogies used in WAG-5 and WAM-4 locomotives, the WAG-7 was given high-adhesion Co-Co bogies ( a modified indigenous variant of the WAG-6 bogies). They also had the Hitachi HS15250A seen in present day WCAM-3 and WCAG-1.

Traction Motors a variant of the standard HS15250 with higher current rating (thicker wire gauge, better insulation); Motors built by CLW and BHEL. 6 motors in parallel grouping
Traction Motors Class of Insulation for Armature and Field C
Traction Motors Suspension Axle hung and Nose-suspended
Traction Motors Weight 3,650 kg (8,050 lb)
Traction Motors Temperature rise in Armature 90 degrees Celsius (194 degrees Fahrenheit)
Traction Motors Temperature Rise in Field 70 degrees Celsius (158 degrees Fahrenheit)
Traction Motors Temperature rise in Commutator 85 degrees Celsius (185 degrees Fahrenheit)
Traction Motors Coil resistance at 110 degrees Celsius (230 degrees Fahrenheit) of Armature 0.0126 ohms
Traction Motors Coil resistance at 110 degrees Celsius (230 degrees Fahrenheit) of Main pole 0.0117 ohms
Traction Motors Coil resistance at 110 degrees Celsius (230 degrees Fahrenheit) of Inter pole 0.0089 ohms
Traction Motors Continuous rating 630 kW (840 hp), 750 V, 900 A, 895 rpm
Traction Motors rating for 1 hour 670 kW (900 hp), 750 V, 960 A, 877 rpm
Traction Motors Air gap for Main pole 6.35 mm (0.250 in)
Traction Motors Air gap for Inter pole 10 mm (0.394 in)
Gear Ratio WAG-7 : 65:16 and 18:64 and WAG-7H : 65:16
Transformer CCL India, type CGTT-5400, Primary rating (5670 kVA, 252 A) Secondary rating (5400 kVA, 1000 V, 5400 A), Tertiary rating 270 V, 32 taps, 12,200 kg (26,900 lb), Forced Oil cooling, Class A Insulation
Rectifiers Two silicon rectifiers, cell type S18FN350 (from Hind Rectifier), 64 per bridge, Continuous rating 2700 A / 1050 V per cubicle, Max starting current 3300 A, Forced air cooling
Pantographs Two Stone India (Calcutta) type AM-12, 235 kg (518 lb) including 4 insulators
Bogie drive arrangement Gear pinion
Current Ratings 1350 A/2min, 1200 A/10min, 960 A/hr, 900 A continuous
Number of sandboxes 8
Permanent shunt 5%
2 Headlights 32 V, 50 W
Lead Acid batteries 50 cells, 110 V(5 hour rating)
Arno Converter Input 216 kVA, 415 V, 1 phase 520 A
Arno Converter Out put 150 kVA, 415 V, 3 phase 210 A, 1485 rpm
2 TRC-2000 type Compressors by Elgi 10.5 kg/cm2 (149 psi)
2 Compressor Motors 30 hp (22 kW), 415 V, 930 rpm
2 Exhauster Motors 7.5 kW (10.1 hp), 415 V, 970 rpm
2 250 RE type Exhausters by Northey 4,500 L/min (990 imp gal/min; 1,200 US gal/min)
2 SF India Ltd. Traction Motor Blowers 276 m3/min (9,700 cu ft/min)
2 Traction Motor Blower Motors by Siemens 415 V, 26 kW (35 hp), 50 A, 2920 rpm
2 PFT-59 type Smoothing Reactors by SF India Ltd. 4,200 m3/min (150,000 cu ft/min)
2 Smoothing Reactor Motors 2.2 kW (3.0 hp), 415 V, 2860 rpm
2 KDBR-1 type Breaking Resistor Blowers by KEC International 510 m3/min (18,000 cu ft/min)
Breaking Resistor Blower Motor 30 kW (40 hp), 450 V, 76 A DC, 3300 rpm
Brushes grade EG1055/BG 1165 (Margnite)
Brushes type 2 split
Brushes size 200 mm × 40 mm × 64 mm (7.874 in × 1.575 in × 2.520 in)
Brushes Wear limit 25 mm (0.984 in)
2 PHMX-40-6 type Rectifier Blowers by SF India Ltd. 3,100–3,200 m3/h (110,000–110,000 cu ft/h)
2 Rectifier Blower Motors 2.2 kW (3.0 hp), 415 V, 4.8A, 2860 rpm
MLBH-60-1-H2 type Coil Cooler Blower by SF India Ltd. 22,200 m3/h (780,000 cu ft/h)
Coil Cooler Blower Motor 22 kW (30 hp), 415 V, 45 A, 1450 rpm
Oil Pump by Best & Co. Pvt. Ltd. 730 L/min (160 imp gal/min; 190 US gal/min)
Oil Pump Motor 32 kW (43 hp), 415 V, 2865 rpm
2 SL 30 type Smoothing Reactors 1250 V, 1350 A
Smoothing Reactor Resistance at 110 degrees Celsius (230 degrees Fahrenheit) 0.00344 ohms

Locomotive sheds
ZoneNameShed CodeQuantity
Central RailwayAjniAQ48
KalyanKYN56
Eastern RailwayAsansolASN35
East Central RailwayPt. DD Upadhyaya JunctionDDU120
DDU (D)50
GomohGMO2
East Coast RailwayAngulANGL216
Northern RailwayLudhianaLDH55
LDH(D)51
KhanalampuraKJGY58
North Central RailwayJhansiJHS90
KanpurCNB77
North Eastern RailwayGondaGD(D)55
Southern RailwayErodeED98
ED(D)24
South Central RailwayVijayawadaBZA112
KazipetKZJ120
KZJ(D)30
GuntakalGTL(D)40
South Eastern RailwayTatanagarTATA39
BondamundaBNDM126
Bokaro Steel CityBKSC80
BKSC (D)60
KharagpurKGP(D)50
South East Central RailwayBhilaiBIA118
Western RailwayValsadBL68
West Central RailwayNew Katni Jn.NKJ81
Total Locomotives Active as of 01-08-2020[6]1959

Performance

WAG-7 with a gear ratio of 18:64 has the following capacity while hauling BOX wagons (in tonnes):

Level/GradeStart20 Unit?30405060708090100Unit?
Level7500+7500+7500+7500+7500+7500+7500+7500+52363732
1 in 5005859 tonnes?585958595859585957654555380827142003
1 in 2004065406540654065398231252510213515401148
1 in 150346833303272321031452476199517031229916
1 in 10026692294226522342201173614011198861638
1 in 5015121149114011311121879704599419300

WAG-7 with a gear ratio of 18:64 has the following capacity while hauling BOXN wagons (in tonnes):

Level/GradeStart2030405060708090100
Level7500+7500+7500+7500+7500+7500+7500+7500+54043793
1 in 5006836683668366836683660164712390427592021
1 in 2004516443343284209408831982558216615551154
1 in 150379034253361328832122523202617231238920
1 in 10028592340230822722233175914161208866640
1 in 5015751161115211411130885708602420300

WAG-7 with a gear ratio of 65:16 has the following capacity while hauling BOXN wagons (in tonnes):

Level/GradeStart2030405060708090100
Level108157500+7500+7500+7500+7500+7500+730246192785
1 in 5007169716971697169716961925005346523451465
1 in 200473847384738473840853285271519151295820
1 in 150397739603880379532102590215015151020645
1 in 10030022705266526252225180515001055725450
1 in 5017001345133513201120905750515--

WAG-7H has the following capacity while hauling BOX wagons (in tonnes) :

Level/GradeStart20304050607080
Level6000+6000+6000+6000+6000+6000+6000+6000+
1 in 5006000+6000+6000+6000+6000+593048353380
1 in 20043504350435043504040321026651885
1 in 15037103710371037053245254521151500
1 in 10028552655262025802195178014851045
1 in 5016601330132013101110895745510

WAG-7H has the following capacity while hauling BOXN wagons (in tonnes) :

Level/GradeStart20304050607080
Level6000+6000+6000+6000+6000+6000+6000+6000+
1 in 5006000+6000+6000+6000+6000+6000+50053465
1 in 20048354835483548354085328527151915
1 in 15041353960388037953210259021501515
1 in 10030602705266526252225180515001055
1 in 5017301345133513201120905750515
  • Compare the two different classes with exactly the same horsepower and almost similar shells
  • BHEL made Erode WAG-7 (TigerFace) locomotive with freight train
  • WAG-7 (old variant) belonging to Electric Loco Shed, Kazipet
  • Jhansi based WAG 7 loco - 27072 with BTPN (Tank-car rakes)
  • Lallaguda WAG-7 (28068) with a Freight train
  • WAG-7 (27486) of Erode with a freight train at Pithapuram
  • WAG 7 locomotive of Mughalsarai shed
  • A WAG 7 loco of New Katni Junction Loco shed
  • WAG-7 class electric locomotive of Indian Railways
  • VSKP - SC Special with a WAG7 loco incharge
  • WAG-7 locomotive of Valsad (BL) Shed
  • WAG-7 of Kanpur (CNB) shed
  • Bondamunda(BNDM) based WAG-7 (old varient) at Toranagallu Junction
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See also

References
  1. "Trainweb WAG-7".
  2. "Trainweb WAG-7H".
  3. "Report of the expert Committee on Coal Consumption on Railways, 1958". INDIAN CULTURE. Retrieved 29 April 2020.
  4. "[IRFCA] Indian Railways FAQ: Locomotives - General Information - I". www.irfca.org. Retrieved 18 April 2020.
  5. "The WAG Series". 24 Coaches. 30 October 2013. Retrieved 29 April 2020.
  6. "e-Locos".
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