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The Indian locomotive classesWAM-2 andWAM-3 were 25kVACelectric locomotives that were imported fromJapan in the 1960s forIndian Railways. The model's name stands forbroad gauge (W),alternating current (A),Mixed traffic (M) locomotive, 2nd generation (2). A total of 38 WAM-2/3 locomotives were built by a consortium, comprisingMitsubishi,Hitachi andToshiba, between 1960 and 1964. These locomotives entered service in 1960.
The WAM-2 and WAM-3 classes served bothpassenger andfreight trains for over 40 years. As of January 2020, these locomotives are no longer in service.
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These locomotives were built by a consortium of Mitsubishi, Hitachi and Toshiba (The Japanese Group, as attested by a plaque fixed on their sides) as an alternative to the European-builtWAM-1.[1] They were delivered in 1960 and were slightly less powerful than the WAM-1 but had similar Bo-Bo wheel arrangement (4 wheels per bogie) with four Mitsubishi DC traction motors connected to the wheels permanently in parallel through a WN[expand acronym] geared drive.[2] The WAM-2 had Ignitron rectifiers just like the WAM-1 but some were later refitted with Exciton rectifiers. Some even had the Mitsubishi logo painted on their sides.
38 locomotives were produced in two batches, with the initial batch of 10 locos having air brakes for the loco and vacuum train brakes, and the second batch of 26 having only vacuum brakes. These have not been retrofitted with air train brakes. Like the WAM-1, they were also used around the ER-SER-NER-NR circuit as it was the first AC electrified area and hauled ordinary passenger and freight trains and sometimes ran all the way toNew Delhi viaKanpur. They were also used double-headed for freight trains. They had four traction motors permanently coupled in parallel are fed by ignitron rectifiers. Speed control is by a tap changer on the input transformer. Mitsubishi transformer, 20 taps. Oerlikon exhaust and compressor, Arno rotary converter. They were based atAsansol Loco Shed ofEastern Railways.
In February 1980, the WAM-2/3 classes had their top speed increased from 100 km/h to 120 km/h by RDSO.[3] This was done for haulage of theHowrah Rajdhani betweenHowrah andGhaziabad on theEastern andNorthern railway division respectively. When theSealdah suburban system was electrified under AC, there was a shortage of AC-voltageelectric multiple units, and so on an interim basis some WAM-2 units were used on push-pull rakes (with the WAM-2 sandwiched in the middle) until the supplies were received, and ER also retrofitted DC EMU stock, though the latter largely operated in theHowrah division, which required dual-voltage capability.
Circulars[who?] at that time[when?] claimed that the withdrawal of the WAM-2 locomotives should be done because they had reached their design lifespan of 35 years. Since they had less than five years of service life remaining, the vacuum brake-fitted WAM-2/3 locomotives were never considered for retrofitting with air or dual brakes. The lifespan of certain WAM-2/3 locos could certainly be extended another five years of revenue service since they were in great condition.[according to whom?] Instead, orders[from whom?] were in place to rapidly decommission these locos.[when?] It happened in such a hurry that not a single WAM-2/WAM-3locomotive could be preserved or plinthed in process.
TheWAM-3 class consisted of two modified WAM2 locomotives, #20333 and #20337 of the Asansol ASN shed of Eastern Railway. They were rebuilt with their pantographs aligned the other way around (pointing outwards) and fitted with silicon diode rectifiers as permanent features, thereby increasing their performance and durability, but were identical to the WAM-2 in every other respect.[4] AsWAM-4s became more common the WAM-3 were relegated to secondary passenger and shunting duties.[5][better source needed]
Four WAM-2s ofAsansol shed were re-geared with the intention of increasing the speed of the class.[when?] The Bo-Bo bogies and WN geared drives of the WAM-2 were replaced by Flexcoil fabricated bogies and axle-hung traction motors respectively. These ran for quite some time and even hauled theHowrah Rajdhani for some time but were decommissioned in the late 1980s. The Indian Railways Fan Club has called the locomotive design an "odd experiment".[4][6]
All locomotives of this class had been withdrawn from service.
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| DC electric |
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| AC electric |
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| Dual (AC and DC) electric |
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| Dual mode |
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