The Indian locomotive classWCAM–3 is a class of dual-power AC/DC serieselectric locomotives That was developed in 1997 byBharat Heavy Electricals Limited used in theIndian Railways system. They are the third locomotives from the WCAM class. The model name stands for broad gauge (W), DC Current (C), AC Current (A), Mixed traffic (M) locomotive, 3rd generation (3). They entered service in 1997. A total of 53 WCAM-3 were built at BHEL between 1997 and 1998, which made them the most numerous class of mainline dual-power AC-DC electric locomotive. They were specifically designed for use byCentral Railways in the Ghat section towardsNashik andPune.
The WCAM-3 locomotives were developed after Central Railways faced a massive locomotive crisis in the 1990s. During this period, many of the WCM locomotives, which began to show their age, suffered several failures. As a result, CR had a tough time in maintaining train schedules, which led to the demand for a locomotive similar to theWCAM-2/2P, which was already successful in theWestern Railways. Thus the WCAM-3 was introduced along with the WCAG-1, with more power and traction.
The locomotive class was jointly developed by RDSO and BHEL in 1997. Components were shared with the WCAG-1 locos (see below), such as High-Adhesion fabricated bogies shared with other locomotives such as theWCAG-1,WAG-7 andWDG-2, with secondary suspension, Monocoque underframe, and Air brakes as original equipment. They were originally manufactured under a BOLT (build-own-lease-transfer) contract with BHEL, and were probably still owned by BHEL rather than by IR. Additionally, they have axle-hung, nose-suspended, force ventilated, taper roller bearings Speed control by tap changers in AC mode and resistance notching in DC mode. Motors can be placed in different series-parallel combinations, with auxiliaries from Elgi, S F India, Best, Gresham & Craven, etc.
The locomotive features a static converter from ACEC for auxiliary supply. In DC mode, rheostatic braking by self-excitation of traction motors available until 17 km/h. It has an elgi compressor, other auxiliaries from S F India. They have been rated to run at 105 km/h in DC mode and AC mode.Traction motor configurations as in the WCAM-1/2 and WAM-4 (all 6 in series, 2S 3P, or all parallel—the latter was the only one used under AC traction, enforced now by modifications to the locos).
The class are in active service in theCentral Railway zone.[when?] CR uses WCAM-3 locos on Mumbai-Pune, Diva-Ratnagiri and Mumbai-Igatpuri sections which had ghat portions as well as speed restrictions of about 100 km/h. They also used to haul intercity trains out of Mumbai DC suburban region onWestern as well asCentral Railway which was on a 1.5 kV DC overhead system, as opposed to other parts ofIndia which had 25 kV 50 Hz AC overhead.[1][irrelevant citation] WCAM[which?] engines now[when?] serve trains operating out ofChhatrapati Shivaji Maharaj Terminus (CSMT) and as bankers on Kasara-Igatpuri/Karjat-Lonavla section. Due to exclusivity in operation/maintenance of these locomotives, they do not go beyond the Central Railway's zone limits. These dual-traction models deliver 4600 hp in DC mode and 5000 hp in AC mode. From 2014, when the Central Line was converted to 25 kV traction, the WCAM-3 were fully transformed into pure AC locomotives by removing the DC equipment, and the performance had improved. These locomotives began to run betweenPune andKolhapur after electrification was completed in 2022.[2]
Freight rakes double-headed by WCAM-3 (upgraded models) are a common sight on the ghat sections. MU operation is possible with 3-4 units. In December 2005, all WCAM-3 locos had been retrofitted with roof-mounted rheostatic braking grids. The acceleration is similar to those ofWAP-4s and sometimes, it is quoted to match the acceleration levels ofWAP-7s, although it's not been verified.[citation needed]
Between 2022 and 2024, 41-WCAM-3 locomotives were converted to WAG-7M, while the remaining locomotives are used for passenger duties. For the conversion, these locomotives had their gear ratios changed from 18:64 to 16:65.
