Indian locomotive class WAM-4

The Indian locomotive class WAM-4 is a class of 25 kV AC electric locomotives that was developed in the 1970 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), AC Current (A), Mixed traffic (M) engine, 4th generation (4). They entered service in March 1971. A total of 500 WAM-4 were built at CLW between 1970 and 1983, which made them the most numerous class of mainline electric locomotive till its successor the WAG-5.

Indian locomotive class WAM-4
AJJ WAM-4 hauling an express train
Type and origin
Power typeElectric
DesignerRDSO
BuilderCLW
Build date1970–1983
Total produced
  • WAM-4: 500
  • WAG-5: 53
RebuilderCLW
Rebuild date1978–1983 to WAG-5
Number rebuilt53
Specifications
Configuration:
​
 • AARC-C
 • UICCo′Co′
 • CommonwealthCo+Co
Gauge5 ft 6 in (1,676 mm)
BogiesALCO Asymmetric cast frame trimount
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)
Wheelbase2,108 mm (6 ft 11 in)
Length:
​
 • Over couplers19,975 mm (65 ft 6 in)
 • Body18,680 mm (61 ft 3 in)
Width3,055 mm (10 ft 0 in)
Height4,162 mm (13 ft 8 in)
Frame typeAsymmetric cast frame
Axle load18.8 tonnes (18.5 long tons; 20.7 short tons)
Loco weight112.8 tonnes (111.0 long tons; 124.3 short tons)
Sandbox cap.16 units X 30 t (30 long tons; 33 short tons)
Power supply110 V DC Supply
Electric system/s25 kV 50 Hz AC Overhead
Current pickup(s)Pantograph
GeneratorHEIL BOT 3460 A
Traction motorsAlsthom TAO 659A1
 • Rating 1 hour770 HP. 750 V, 840 A, 1095 RPM
 • Continuous798 HP. 750 V, 870 A, 1070 RPM
Head end power110 V DC Supply
TransmissionElectrical
Gear ratio15:62
MU working4 units
Loco brakeAir, Rheostatic braking
Train brakesAir, Vacuum and Dual
Safety systemsSlip control, Over voltage relay, No volt relay, Earth fault relay, Low pressure governor, Train parting alarms, and Brake cylinder cutoff valve
Performance figures
Maximum speed120 km/h (75 mph)
Power output3,640 hp (2,710 kW)
Tractive effort:
​
 • Starting33,840 kgf (331.9 kN; 74,600 lbf)
 • 1 hour30,000 kgf (290 kN; 66,000 lbf)
 • Continuous17,600 kgf (173 kN; 39,000 lbf)
Career
OperatorsIndian Railways
ClassWAM-4
Numbers
  • WAM-4B 20400–20699, 21200–21399
  • WAG-5: 21100-21138
NicknamesAnanth, RAJATABHA, Surubhi, Navchetna, Sukh Sagar, Naveen
LocaleAll over India
Delivered4 December 1970
First runMarch 1971 (1971-03)
Last runFebruary 2020 (2020-02)
Preserved6 units

The WAM-4 is one of the most successful locomotives of Indian Railways having served both passenger and freight trains for over 50 years. This class provided the basic design for a number of other locomotives like WCAM-1, WAG-5A, WCG-2, and some WAP models. However, with the advent of new 3-phase locomotives like WAP-5 and WAP-7, the WAM-4 locomotives were relegated to hauling smaller passenger trains and now the aging fleet the WAM-4 locomotives are being rapidly scrapped and have been fully withdrawn from mainline duties.

History

The history of WAM-4 begins in early 1970s with the aim of addressing the shortcomings of the previous WAM-1/2 and WAG(1-4) classes and remove steam locomotives from IR by a target date of 1990. The WAM-1s were not great successes as some of their advanced features were unsuitable for Indian conditions.

so the designers at RDSO and CLW decided to use the following

  • Instead of the Bo-Bo bogies of WAM-1/2, ALCO asymmetric Trimount bogies of the WDM-2 were provided for better traction and power.
  • Silicon rectifiers with speed control by three series-parallel motor combinations and weak field operation.
  • Auxiliaries from Westinghouse and Kirloskar (compressors), S F India (blowers) and Northey (exhauster)
  • Air brakes for loco and vacuum train brakes fitted as original equipment with Rheostatic braking also provided
  • MU operation made possible up to 4 units possible.

Production of these locomotives started in 1970 with #20400 and exactly 500 WAM-4s were built in 13 years with #21399 “Anant” being the last one. Production ended on August 3, 1983.WAM-4 though an indigenously produced loco was heavily inspired by French box design and naturally favoured a French TM which was the Alstom made TAO TM. A single WAM-4 can generally haul up to a 24-coach passenger rake.This class proved so successful by virtue of its ruggedness suitable for Indian conditions and simplicity of maintenance,

Variants

This loco class has been seen in many variations, as a lot of workshops and sheds have carried out their own enhancements or modifications to the basic loco design. Although the code indicates a mixed-use loco, most WAM-4's ended up hauling passenger trains.

Variants include

  • WAM4B or G: Freight only (re geared version)
  • WAM4D or DB: Dual Braked (Air and Vacuum)
  • WAM4E: Air Brake only (for both loco and train)
  • WAM4H: Hitachi Traction Motors instead of Alstom
  • WAM4P: Passenger only (re geared version)
  • WAM4/2S3P: 2 Traction Motors in Series, 3 in Parallel
  • WAM4/6P: 6 traction motors permanently in parallel
  • WAM4/6PE: Air braked, 6 Traction Motors perm. in parallel
  • WAM4/6PDBHS: 6 Traction Motors permanently in parallel, Dual Brakes, High Speed
  • WAM-4P D: Passenger only (dual brakes)
  • WAM-4P DB 6P and WAM-4 6P D: These are for superfast trains
  • WAM-4P DB 3P and WAM-4 2S-3P: some superfasts, passengers

The 'DB' or 'D' generally, but perhaps not always, indicates dual-brake capability. 'HS' may be for 'high speed'.'2S', '3P', '6P', etc. indicate traction motors connected in series or parallel. The WAM-4 has six traction motors, and originally they were wired to be available in different configurations at different power settings. At notches up to 14, all motors were in series (at notch 14 all resistors dropping out); up to notch 21 in series-parallel combinations (three pairs of motors in series, the pairs themselves being in parallel); and further notches with all motors in parallel (at notch 30 all motors are in parallel with resistors dropping out). This is the original configuration of the WCAM-1 series of locomotives too.

The WAM-4 locomotives were later reconfigured to have all motors always in parallel (6P variants) or with the three series-connected pairs in parallel (2S 3P variants). Some WAM-4 locomotives from CLW are thought to have had the 2S 3P configuration right from the start. The 2S 3P configuration was better for the mixed traffic loads especially as it allowed the locomotives to start hauling larger loads without stalling. With increasing use of the WAM-4 locomotives for passenger traffic the all-parallel configuration was deemed more desirable since it allowed higher speeds and higher acceleration.

Livery

This loco has the widest variety of liveries, with each loco shed having its own livery

Most of the WAM-4 locomotives now have their MU capability disabled as RDSO disapproves of these locomotives running MU'd over 100 km/h. [1]

Named locomotives

A few WAM-4 locomotives have been named by Indian Railways[2]

List of Named locomotives
Class Loco Number Name Loco Shed Current status ref
WAM-4 20401 Rajatabha Bhillai [BIA] Condemned [07/08/2007] [3]
WAM-4 20420 Sukh Sagar Naveen Vijayawada [BZA] Scrapped [4]
WAM-4 20615 Surubhi Aasansol [ASN] Condemned in November 2011 [5]
WAM-4 21320 Garuda Arakkonam [AJJ] Plinthed at Rail Soudha, SWR HQ, Hubli [January 2020] [6]
WAM-4 21380 Navchetna Asansol [ASL] In Inferior service [7]
WAM-4 21399 Anant Bhusawal [BSL] The last WAM-4 ever built. No longer in holdings - assumed withdrawn/scrapped [January 2019 [8]

Preserved Examples

A few WAM-4 locomotives have been preserved by Indian Railways at various location around India[9][10]

Class Loco Number Previous shed Name LIvery Location ref
WAM-4 20400 BIA BIA cream/orange with blue stripe Used at Electric Loco Training Center, Uslapur [October 2011]. Reumbered ELTC-120 [11]
WAM-4 20472 Ghaziabad (GZB) Restricted to shunting/departmental duties only. Earmarked for preservation: I.R. Heritage Website [November 2018] [12]
WAM-4 20484 Bhusawal (BSL) BSL cream/orange with orange lining Loco now preserved at CLW loco park [13][14]
WAM-4 20601 Jhansi (JHS) Maroon with cream band Earmarked for preservation: I.R. Heritage Website [November 2018] [15]
WAM-4 21320 Arakkonam (AJJ) Garuda Red/dark grey/light grey with white line Plinthed at Rail Soudha, SWR HQ, Hubli [January 2020] [16]
WAG-5/WAM-4B 21101 Tatanagar (TATA) Brown/Black with Yellow stripe Plinthed outside TATA [17]

Locomotive sheds
ZoneNameShed CodeQuantity
Eastern Railway AsansolASN3
Northern RailwayGhaziabadGZB1
LudhianaLDH1
North Central RailwayKanpurCNB3
South Eastern RailwayTatanagarTATA4
South East Central RailwayBhilaiBIA4
Total Locomotives Active as of 01-06-2020[18]16

Technical specifications[19]
Traction Motors Alstom TAO 659 A1 (575 kW, 750 V). Six motors, axle-hung, nose-suspended, force-ventilated.
Gear Ratio 15:62 originally (and still for WAM-4 2S3P), now many variations, 21:58 being common for WAM-4 6P locomotives.
Transformer Heil BOT 3460 A, 22.5 kV / 3460 kVA.
Rectifiers Two silicon rectifier cells, 1270 V / 1000 A each cubicle.
Pantographs Two Faiveley AM-12.
Hauling capacity 2,010 t (1,980 long tons; 2,220 short tons)
Current Ratings (WAM-4 6P) 1100A/10min, 750A continuous
  • WAM 4 series loco 20491 from Vadodara Shed VSKP-Nanded Express
  • WAM 4 series loco 21226 from Visakhapatnam Shed spotted at Moula Ali
  • WAM 4 series loco 21219 from Arakkonam Shed spotted at Visakhapatnam Junction
  • 13022 (Raxaul - Howrah) Mithila Express with HWH WAM 4 21281 based at katni shed
  • WAM-4P loco of Vijayawada Shed spotted at Secunderabad
  • WAM 4 with the Malwa Express
  • 12295 (SBC-PNBE) Sanghamitra Express from Mughalsarai Shed
  • Howrah bound 12814 (Tatanagar-Howrah) Steel Express with WAM4 series loco of Tata shed

See also

References

Notes
  1. http://www.irfca.org/faq/faq-loco2e.html
  2. "[IRFCA] Indian Railways Locomotive Roster List". www.irfca.org. Retrieved 14 April 2020.
  3. https://www.irfca.org/apps/locos/show/4489?list_type=named&page=10
  4. https://www.irfca.org/apps/locos/show/4508?list_type=named&page=10
  5. https://www.irfca.org/apps/locos/show/4703?list_type=named&page=10
  6. https://www.irfca.org/apps/locos/show/4908?list_type=named&page=10
  7. https://www.irfca.org/apps/locos/show/4968?list_type=named&page=10
  8. https://www.irfca.org/apps/locos/show/4987?list_type=named&page=10
  9. "Ministry of Railways (Railway Board)". www.indianrailways.gov.in. Retrieved 14 April 2020.
  10. "preserve loco list".
  11. https://www.irfca.org/apps/locos/show/4488?list_type=preserved&page=2
  12. https://www.irfca.org/apps/locos/show/4560?list_type=preserved&page=2
  13. https://www.irfca.org/apps/locos/show/4572?list_type=preserved&page=2
  14. "wam4". www.irfca.org. Retrieved 14 April 2020.
  15. https://www.irfca.org/apps/locos/show/4689?list_type=preserved&page=2
  16. https://www.irfca.org/apps/locos/show/4908?list_type=preserved&page=2
  17. https://www.irfca.org/apps/locos/show/8152?list_type=preserved&page=2
  18. "e-Locos".
  19. Indian AC electric loco information

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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