Indian locomotive class WAP-4

The WAP-4 (Wide gauge, AC traction, Passenger service, 4th in series) is a class of passenger hauling electric locomotive used in Indian Railways.

WAP-4
A WAP-4 hauls the Swarna Jayanti Express.
Type and origin
Power typeElectric
BuilderChittaranjan Locomotive Works, West Bengal, India
Build date1993 till 2 December 2015
Total produced778 as of August 2016 (Production Ceased)
Specifications
Configuration:
​
 • AARC-C
 • UICCo'-Co'
Gauge5 ft 6 in (1,676 mm)
BogiesCo-Co Flexicoil Mark 90 cast bogies; primary and secondary wheel springs with bolsters
Wheel diameterNew:1,092 mm (3 ft 7 in)
Half worn: 1,055 mm (3 ft 5 1⁄2 in)
Full worn: 1,016 mm (3 ft 4 in)
Length18.794 m (61 ft 7 29⁄32 in)
Width3.179 m (10 ft 5 5⁄32 in)
Height4.272 m (14 ft 3⁄16 in)
Axle load18,800 kg (41,400 lb)
Loco weight112,800 kg (248,700 lb)
Electric system/s25 kV 50 Hz AC Overhead
Current pickup(s)pantograph
Traction motorsHitachi HS15250
Loco brakeAir
Train brakesAir
Safety systemsSlip control, Over voltage relay, Main overload relay, Earth Fault Relay, Low Pressure Governor, Brake Cylinder Cutoff Valve, Train parting alarms and No OHE volt relay
Performance figures
Maximum speed140 km/h (87 mph)
Power outputContinuous: 5,050 hp (3,766 kW)
Tractive effortStarting : 30,800 kgf (302 kN; 68,000 lbf)
Career
OperatorsIndian Railways
Numbers22061 and from 22201-22399 and 22500-22999 and 25000-25051
LocaleAll over India
DispositionActive

The locomotive was developed after its predecessor, the WAP-1, was found inadequate to haul the longer, heavier express trains (24-26 coaches) that were becoming the mainstay of the Indian Railways network. It was introduced in 1994, with a similar body-shell to the WAP-1 class, but with Hitachi traction motors. The electrical systems are traditional direct-current loco type tap changers, driving six traction motors arranged in Co-Co fashion. The locomotive has proved to be highly successful, with more than 750 units in service. Newer examples have been fitted with microprocessor-controlled diagnostics, static converter units (instead of arnos) and roof-mounted dynamic (rheostatic) brakes. The locomotive can be seen in service across the entire electrified network of Indian Railways and is homed at 14 locomotive sheds.

Production of this class was halted in December 2015 with locomotive number 25051 being the last unit to be rolled out of Chittaranjan Locomotive Works.

Design

The loco has a streamlined twin cab carbody design, with twin beam, top-mounted headlamps. The first 150 or so units had the headlamp mounted at waist level, with the lights being mounted in a protruding nacelle. Some earlier locos, especially from the Erode loco shed have the headlamps placed on the top. Later on the headlamps were placed in a recessed nacelle, and from road #22579 onward, the headlamps were moved to the top.

The loco is equipped with digital notch repeaters. Newer locos also feature larger windshields, more spacious driver cabin with bucket seats and ergonomic controls. The control panel has a mix of digital and analog displays in newer units while the older units were mostly analog.

Original units weighed 120 tonnes, which was later brought down to 112 tonnes through the usage of lighter material.

Some of the WAP-1 and WAP-3 and all the WAP-6 units were rebuilt to WAP-4 specifications after replacing the bogies & electricals.

It has different underframe for handling larger buffing loads. Some units are fitted with speed recorders and some changes to control electronics. Some units also have data recorders for energy consumption. Some are even fitted with windshield washers and rearview mirrors. Few were provided with signalling lamps which were subsequently removed.

Technical variants include WAP-4E which are probably fitted with electronic sensors for sensing pipe pressure loss.

The Hitachi traction motors are the ones used on freight engines. It was a challenge to put these in a passenger engine due to weight constraints. So the transformer is aluminum foil-wound and aluminum chequered plates are used for reducing the weight.

415 volts, three-phase, 50 Hz power supply is used to drive various auxiliary motors like (1) Traction motor blowers (2) Transformer radiater blower (3) Transformer oil pump (4) Smoothing Reactor Blowers (5) Silicon Rectifier Blowers (6) Battery charger. The three-phase, 415 volt supply is obtained from the single phase supply by Arno converter or static converter.

Indian railways has installed microprocessor based fault diagnostic system and Vigilance Control Device for the enhancement of safety and reliability of electric Locomotives. Some of the newly manufactured WAP-4 locomotives also have air conditioning system for the loco pilot.

Performance

If the average weight of ICF coach is 55 tonnes then it can haul the following capacity in tonnes:

GradientStart20 km/h40 km/h60 km/h70 km/h80 km/h90 km/h100 km/h110 km/h120 km/h130 km/h140 km/h150 km/h160 km/h
Level1500+1500+1500+1500+1500+1500+1500+1500+1500+1500+1500+1155805570
1 in 5001500+1500+1500+1500+1500+1500+1500+1500+1500+1500+1105805565400
1 in 2001500+1500+1500+1500+1500+1500+1500+132012301035730535375260
1 in 1501500+1500+1500+1500+1500+1500+140510901020860610445310215
1 in 1001500+157014901405136511951020795750635445320220145
1 in 5011607707507207106255304103903252201509045

Technical specifications
A WAP-4 Locomotive at Secunderabad
Front view of the WAP-4
Technical Specifications of WAP-4[1]
Gear Ratio 58:23 (One loco, #22559, was said to have a 59:23)
Transformer 5400 kVA, 32 taps
Transformer cooling Forced oil with Forced Air
Transformer Insulation A
Pantographs Two Stone India (Calcutta) AM-12.
Rectifiers Two silicon rectifiers
Rectifier Cooling Forced air
Current Ratings 1300 A for 2 min, 1100 A for 10 min, 960 A for 60 min, 900 A continuous
Drive arrangement Gear pinion
Number of sandboxes 4
2 headlights 90 W, 24 V
Lead acid battery 10 Batteries each of 11 V, 75 Ah Capacity.
Arno Converter 1420 rpm
2 Elgi Compressors 1000 l/minute at 7.5 kg/cm2.
2 compressor motors 3 phase 12.5 hp and 380 V
2 SF India Ltd. Traction motor blowers MLBR-42.5-144 type
2 Siemens Traction motor blower motors 22 kW, 415 V, 50 A and 2820 rpm
2 SF India Ltd. Smoothing Reactor Blower PFTA-50, ARR6 type
Traction Motor Suspension Axle-hung, nose suspended
Traction motor weight 3650 kg
Armature temperature rise 90 °C
Field temperature rise 70 °C
Commutator temperature rise 85 °C
Armature coil resistance at 110 °C 0.0126 ohms
Field coil resistance at 110 °C 0.0117 ohms
Commutator coil resistance at 110 °C 0.089 ohms
Traction motor continuous rating 675 kW (905 hp), 750 V, 900 A and 895 rpm
Traction motor 1 hour rating 1030 hp, 750 V and 877 rpm
Traction Motor air gap main place 6.35 mm
Traction motor air gap inter-pole 10 mm
Traction motor 6 P
2 SF India Ltd. silicon rectifier blower 3100–3200 m/hr
2 Rectifier blower motor 22 kW, 415 V, 8 A, 2860 rpm and 60 kg(approx)
Oil cooler blower motor 30 hp, 380 V, 43 A and 1450 rpm
BEST and Co. Pvt. Ltd. Transformer Oil Pump 750 l/minute
Oil pump motor 3.3 kW, 415 V, 6.6 A and 2865 rpm
SL-30 type smoothing reactor 1250 V and 1350 A.
Smoothing reactor resistance at 110 °C 0.00718 ohms
Notches 32
  • WAP-4 loco of Erode shed; Erode owns highest no. of WAP 4 locomotives
  • Indian Locomotive WAP-4 Erode
  • 22530, off POH+RC+RP @ KPA, 16-02-2019
  • ELS Arakkonam Jn.
  • WAP4-22291Howrah
  • Ghaziabad based WAP 4 with large model number similar to Ghaziabad based WAP 5 & WAP 7
  • A WAP 4 hauls Swarn Jayanti express
  • SRC WAP 4 with Ispat express

Locomotive sheds
ZoneNameShed Code Quantity
Central RailwayBhusawalBSL 43
Eastern Railway Asansol ASN 18
HowrahHWH 73
East Central Railway Pt. DD Upadhyaya Junction DDU 92
East Coast Railway Visakhapatnam VSKP 21
Northern Railway Tughlakabad TKD(D) 29
North Central Railway Jhansi JHS 18
Kanpur CNB 30
North Eastern Railway Gonda GD(D) 13
Southern Railway Arakkonam AJJ 90
Erode ED 61
South Central Railway Vijayawada BZA 68
South Eastern Railway Santragachi SRC 70
Western Railway VadodaraBRC 32
Valsad BL 35
Vatva VTA(D) 5
West Central Railway ItarsiET 75
Total Locomotives Active as of 01-08-2020[2] 773
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See also

References

Notes
  1. "Indian AC electric loco information". Irfca.org. Retrieved 3 April 2013.
  2. "e-Locos".

Bibliography
  • Hughes, Hugh (1996). Indian Locomotives: Part 4 – 1941–1990. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9521655-1-1.
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