Indian locomotive class WAM-4

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WAM-4
Arakkonam based WAM-4 (now scrapped) heading towards Perambur.
Type and origin Power type Electric Designer RDSO Builder CLW Build date 1970–1983 Total produced WAM-4: 500 WAG-5: 53 Rebuilder CLW Rebuild date 1978–1983 to WAG-5 Number rebuilt 53
Specifications Configuration: ​  • AAR C-C  • UIC Co′Co′  • Commonwealth Co-Co Gauge 5 ft 6 in (1,676 mm) Bogies ALCO Asymmetric cast frame trimount Wheel diameter New: 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) Wheelbase 2,108 mm (6 ft 11 in) Length: ​  • Over couplers 19,975 mm (65 ft 6 in)  • Over body 18,680 mm (61 ft 3 in) Width 3,055 mm (10 ft 0 in) Height 4,162 mm (13 ft 8 in) Frame type Asymmetric cast frame Axle load 18.8 tonnes (18.5 long tons; 20.7 short tons) Loco weight 112.8 tonnes (111.0 long tons; 124.3 short tons) Sandbox cap. 16 units X 30 t (30 long tons; 33 short tons) Power supply 110 V DC Supply Electric system/s 25 kV 50 Hz AC Overhead Current pickup(s) Pantograph Traction motors Alstom TAO 659A1 ​  • Rating 1 hour 770 HP. 750 V, 840 A, 1095 RPM  • Continuous 798 HP. 750 V, 870 A, 1070 RPM Head end power 110 V DC Supply Transmission Electrical Gear ratio 15:62 MU working 4 units Loco brake Air, Rheostatic braking Train brakes Air, Vacuum and Dual Safety systems Slip control, Over voltage relay, No volt relay, Earth fault relay, Low pressure governor, Train parting alarms, and Brake cylinder cutoff valve
Performance figures Maximum speed 120 km/h (75 mph) Power output 3,640 hp (2,710 kW) Tractive effort: ​  • Starting 33,840 kgf (331.9 kN; 74,600 lbf)  • 1 hour 30,000 kgf (290 kN; 66,000 lbf)  • Continuous 17,600 kgf (173 kN; 39,000 lbf)
Career Operators Indian Railways Class WAM-4 Numbers WAM-4B: 20400–20699, 21200–21399 WAG-5: 21100-21138 Nicknames Garuda, Ananth, RAJATABHA, Surubhi, Navchetna, Sukh Sagar, Naveen[citation needed] Locale All over India Delivered 4 December 1970 First run March 1971; 53 years ago (1971-03) Withdrawn May 2023; 1 year ago (2023-05) Preserved 6 units Disposition A few units still in inferior service, rest scrapped

The Indian locomotive class WAM-4 is a class of 25 kV AC electric locomotives that was developed in 1970 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), alternating current (A), mixed traffic (M) locomotive, 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.

The WAM-4 is one of the most successful locomotives of Indian Railways^{[peacock prose]} having served both passenger and freight trains for over 52 years. This class provided the basic design for a number of other locomotives like WCAM-1, WAG-5A, WCG-2, and some WAP-1 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 most of the units have been scrapped. A few units are in service performing backup and non-essential duties.