WAP-4
Arakkonam based WAP-4 hauling Guruvayur 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 weight116,000 kg (256,000 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, 22500-22999 & 25000-25051
LocaleAll over India
DispositionActive

The Indian locomotive class WAP-4 is a class of 25 kV AC electric locomotives that was developed in 1993 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), AC Current (A), Passenger traffic (P) locomotive, 4th generation (4). They entered service in late 1994. A total of 778 WAP-4 were built at CLW between 1993 and 2015, which made them the most numerous class of mainline electric passenger locomotive until the WAP-7.

The WAP-4 is one of the most successful locomotives of Indian Railways serving both passenger and freight trains for over 29 years. This class provided the basic design for other locomotives like the WAP-6 . Despite the introduction of more modern types of locomotives like WAP-7, a significant number are still in use, both in mainline duties. Production of this class was halted in December 2015 with locomotive number 25051 being the last unit to be rolled out.

As of September 2022, all locomotives except those lost in accidents still retain "operational status" on the mainline as WAP-4, with further examples having been converted from WAP-6.

History

Development

The WAP-4 class 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. IR/RDSO had realized that the reason for the WAP-1’s performance problems were the low-powered 770 hp Alstom TAO 659 traction motors. These were previously used with for the WAM-4 and WAG-5 classes but were too underpowered for modern requirements. At that time, new 840 hp Hitachi 15250 traction motors which had been adopted for use on newer WAG-5s was showing promise. So, these traction motors were adopted on to WAP-1s Flex-icoil Mark I fabricated bogies, and with a new indigenously designed 5400 kVA transformer and silicon rectifiers.[1]

It also was among the first locomotives to get a microprocessor-based control and fault diagnostics system. To accommodate the heavier Hitachi motors without increasing its 112t overall weight, the WAP-4 was made substantially lighter by the widespread use of aluminum materials in construction. The underframe of WAP-4 is narrower and lighter and also completely different from that of the WAP-1 to enable it to handle higher loads.[2][3]

Design

(front) newer loco with (back) older series unit

The loco has a streamlined twin cab carbody design, with 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. Later on the headlamps were placed in a recessed nacelle, and from road # 22573 onward, the headlamps were moved to the top. Newer locos also feature larger windshields, more spacious driver cabin with bucket type seats and ergonomic controls. The control panel also features a mix of digital and analog displays in newer units (all analog display in older versions).[4]

Production

The first WAP-4 unit, #22201 rolled out from CLW on April 25, 1994. They looked exactly like the WAP-1, even sporting the same livery. From 2000, newer versions with many WAP-5 design cues like square type windscreens ,twin-beam headlights, speed recorders and some changes to the control electronics had been rolled out recently.

However, in the face of the advent of three-phase AC traction motors, IGBT-controlled AC drives, and full computer controls, the DC traction motors was getting increasingly outdated. So the last unit, #25051 was manufactured on November 1, 2015 making 776 of these locomotives produced over 20 years.[5]

Service

The WAP-4s were developed at the same time IR gave procurement orders for WAP-5 locomotives, as they were meant for more general duties of hauling 24-coach expresses while WAP-5 were specially meant for high-speed operations.

Recently as per directive received from Railway Board [RB] all the loco sheds holding WAP-4 type locomotive have started "Mu" [Multiple Unit] operations. This configuration of Mu WAP-4 locos are being used to haul medium tonnage faster freight trains across IR. The different locomotive sheds of WAP-4 are Arakkonam, Santragachi, Erode, Mughalsarai, Howrah and Bhusaval.[6]

Livery

All WAP-4s are painted in the same red-black with a yellow/cream band livery, though the shade of the red will differ from shed to shed, from the blazing crimson red of Santragachi SRC/SER to the orange of Erode ED/SR.BZA/SCR painted with navy blue livery recently

Locomotive sheds

Zone Shed Name Code Quantity
Central Railway Bhusaval BSL 71
Eastern Railway Asansol ASN 18
Howrah HWH 48
HWH (D) 15
East Central Railway Pt. Deen Dayal Upadhyaya DDU 41
SamastipurSPJ (D)45
Northern Railway Tughlakabad TKD (D) 42
Alambagh AMV (D) 2
North Central Railway Jhansi JHS 38
North Eastern Railway Gorakhpur GKP 44
Izzatnagar IZN (D) 38
North Western Railway Abu Road ABR (D) 8
Southern Railway Arakkonam AJJ 98
Erode ED 36
Erode ED (D) 35
South Central Railway Vijayawada BZA 63
South Eastern Railway Santragachi SRC 60
Western Railway Valsad BL 31
Vatva VTA (D) 30
Ratlam RTM (D) 10
Total locomotives active as of December 2023[7] 773

See also

References

Notes

  1. ↑ https://www.rdso.indianrailways.gov.in/works/uploads/File/29_01_10.pdf
  2. ↑ https://rdso.indianrailways.gov.in/works/uploads/File/Maintenance%20handbook%20on%20Flexicoil%20Bogies%20Mark-I(1).pdf
  3. ↑ https://rdso.indianrailways.gov.in/uploads/files/TC%2074.pdf
  4. ↑ https://www.ijmer.com/papers/Vol4_Issue4/Version-1/A044010114.pdf
  5. ↑ https://rdso.indianrailways.gov.in/works/uploads/File/37th%20MSG%20Minutes.pdf
  6. ↑ "Waltair Division to use WAP-4 model locos for freight operations". 14 September 2020.
  7. ↑ "e-Locos".

Bibliography

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