Electric Locomotive Classes –
DC & Dual current

Note: Information on the WAM, WAG & YAM locomotives can be found here.

Additional details and diagrams of various electric loco classes can be found at Prakash Tendulkar's site.

DC Locomotives

WCP-3, WCP-4 (GIPR EB/1 and EC/1) Wheel arrangements not seen these days, 2-Co-2.

WCG–2 WCG-2Custom-built freight loco for the 1.5 KVDC section of the CR Mumbai Division. Better adhesion available through the provision of a vernier control on the starting resistance. AC auxiliaries — compressor and alternator from Kirloskar, exhauster by Northey (?), others by S F India. Air brakes for loco, and regenerative brakes; vacuum train brakes. Three series-parallel motor combinations weak field operation. Bogie design as with WDM-2.

RDSO designs, based on Japanese models but final design and manufacture was by CLW. These locos can be MU'd up to 3 units. Some units of the WCG-2 model have a different gearing ratio for banking duties and are classified WCG-2A.

This loco has a very loud noise caused by the blowers used to cool the dynamic brake resistors. Mumbai division has about 50 WCG-2s, 57 in all. The WCG-2 locos, normally coupled in pairs or triples, haul freight trains in the Bombay - Igatpuri/Pune sections. They are also used as bankers on the ghat sections. There was a period around 1992 -1996 when the Mumbai division were desperately short of motive power due to the aging and failure prone WCM-1/2/4/5 fleet. The punctuality of trains in and out of CSTM went haywire due to loco failure. During this period the WCG-2 was used on many Mail / Express runs. But the 'Deccan Queen' has been hauled only once by a WCG-2 and only a few times by a WDM-2 when its power, the WCM-1, failed.

The Ghat banking duties in the Bhore ghat (Karjat - Lonavala) and Thull ghat (Kasara - Igatpuri) are exclusively handled today by WCG-2s. On some occasions some express trains are hauled by these (Sinhagad, Cape, Dadar - Chennai, Sahyadri, Koyna, Pragati, etc.). Because of speed restrictions (90km/h) on the Mumbai (CSTM) - Igatpuri route, even superfast trains can be hauled on this section by WCG-2 locos. The WCG-2 shares bogies with the WAM-4, WCAM-1, WCAM-2, WDM-2/2C, WDS-6, WDM-7 locos (Alco type cast trimount (Co-Co) bogies). Now [2/05] the WCG-2 locos are often seen only performing banking duties. Until recently the Koyna Express and Mumbai Passenger were routinely hauled by WCG-2 locos. The Mumbai-Pune Intercity Exp. is also sometimes hauled by WCG-2 locos.

  • Manufacturers: CLW
  • Traction Motors: Heil TM4939AZ (690hp, 700V, 800A, 1070 rpm, weight 3670kg) Six motors, axle-hung, nose-suspended, force-ventilated. (4200hp total power, 1640 1-hour continuous rating in series mode.)
  • Rated Speed: 80km/h (originally), 90km/h with upgrades.
  • Pantographs: Two, Faiveley AM-18B

Comparative Specifications

Dual Current Locomotives

WCAM Locos WCAM is the dual-power AC-DC series. Virar is the change-over point the traction, being DC inwards near Bombay and AC on the outer side. The WCAM class of locos on WR have never operated north of Baroda on the mainline and are generallky restricted to BCT-BRC-ADI section. Apart from WR they can be found working on the harbour line of CR in Bombay into the dockyard railway changeover point a Wadala Road. See the electric traction section for more information on AC/DC traction changeover.

All the WCAM locos (except the WCAM-1 loco built by CLW) and the WCAG-1 loco, were made by BHEL. They have 750V DC traction motors, using resistance banks in DC mode and a variable ratio auto-transformer with rectifier units in AC mode, for power control (WCAM-1 is slightly different, see below). Except for the WCAM-1, the availability of the variable input voltage allows the traction motors to be coupled in a fixed 2S-3P grouping for AC mode. In DC mode, all three models allow 6S and 3S-2P grouping, and the WCAM-3 also allows 2S-3P.

[2/02] Most of CR's WCAM-3 locos do not go north of Igatpuri; a few reach all the way to Manmad (Panchavati, Devagiri, Tapovan, and Godavari Expresses) but not beyond, as the maintenance facilities for these locos do not exist beyond there. On WR, WCAM models generally do not venture beyond Vadodara (main-line trains to New Delhi change to purely AC locos there). Trains to Ahmedabad from Mumbai are usually hauled by WCAM locos all the way. Generally the WCAM locos are restricted to Valsad / Surat.

WCAM–1 WCAM-1Introduced in 1975. This class of loco was generally found only in the Bombay Central - Ahmedabad section. An occasional loco has also appeared on the Bombay V.T. - Igatpuri route.

One of the single pantographs on the WCAM-1 is used in dc traction; the other one carries ac current. The two pantographs are not identical, though similar in design. Bogie design as for WDM-2, WCG-2, and WAM-4 (Alco asymmetric trimount (Co-Co) bogie with cast frames). These locos perform poorly in DC mode compared to AC mode. Originally built with vacuum brakes only, although a few (Nos. 21805, 21807, 21812, 21828, 21838, 21844, 21845, and 21850) have both vacuum and air brakes. Update [1/05] The locos are now restricted to hauling vacuum-braked trains. Loco brakes are air brakes. They also lack dynamic brakes.

The WCAM-1 does not use a variable ratio auto-transformer in AC mode like the others; it uses a fixed-ratio transformer and rectifier bank to convert the OHE supply to 1500VDC. The design of the transformers and notches makes this a hard machine to operate, with the fusible links tending to blow often. Of the 28 notches, notches 4, 14, 21, and 28 can be used for continuous operation, although notch 4 was intended for low-speed shunting and is very ineffective. Notches 14, 21, and 28 are the terminal notches of the series, series-parallel, and parallel circuit notch sequences. In DC mode, the WCAM-1 uses resistor banks for speed control.

However they were very robust machines and relatively easy in the handling characteristics. WCAM-1's have three traction modes (series, series-parallel, parallel) in both DC and AC mode, but using the parallel mode in DC was discouraged because of power problems. In practice this was not restrictive since series-parallel notches allowed reaching 75km/h or so. In AC mode, the locos are almost always used with the motors in all-parallel mode. Unlike the WCAM-2 and WCAM-3 locos, no reconfiguration has been carried out to force the use of all-parallel mode with AC. Weak field operation is available. 53 of these locos were produced. They were briefly tried out for freight use by CR, but all finally ended up with WR.

They are used for WR's second-tier trains, the top ones getting the WCAM-2P (see below). [5/02] However, recently CR's Indore-Pune weekly train has been hauled by a WR WCAM-1.

Recently [2004] it's been seen that some (3-4) WCAM-1 locos have been modified to run only in AC mode; in many cases these locos have even had their DC equipment removed. Such modifications occurred after WR's Virar - Vasai freight lines were converted to AC. The modifications were carried out by the Valsad shed. It is not proposed that the locos will be re-classified; one, #21808, simply bears an annotation saying 'Only AC Working'.

Update on status: [1/05] WR has decided to condemn five WCAM-1 locos: 21801, 21802, 21803, 21804, and 21806.

Max. speed 100km/h, 110km/h after regearing. MU operation not possible. Motor-alternator from Kirloskar (AEI UK motor), Gresham & Craven exhauster, Kirloskar compressor; other auxiliaries from S F India.

  • Manufacturers: CLW
  • Traction Motors: Alstom/CLW TAO 659 A1 (575kW, 750V). Axle-hung, nose-suspended.
  • Wheelsets: Alco asymmetric Co-Co trimount cast bogies.
  • Transformer: BHEL BOT 34600. 3460kVA.
  • Rectifiers: Silicon rectifiers, 48 cells (321 UFR200) per bridge, 1000A/1270V.
  • Gear Ratio: 61:16, 58:21
  • Pantographs: Faiveley AM-12 (AC) and Faiveley AM-18B (DC)
  • Length: 20950mm
  • Total wheelbase: 15698mm
  • Weight: 113t

Comparative Specifications

WCAM–2 WCAM-2PWCAM-2 locos have the same traction motors, as the WCAM-1 locos, but different circuitry and gearing. The bogies are somewhat different from those of the WCAM-1 being fabricated trimount Co-Co bogies with secondary suspension. Rated speed 105km/h in DC mode and 120km/h in AC mode. (In trials by RDSO this loco is said to have been run at speeds up to 135km/h in AC mode.)

Almost all of these are dual-braked, but a few are equipped with air brakes only. Double-header frieghts with these locos are a common sight on the Wadala road-Kings Circle-Mahim-Bandra run. They can also be seen on the Vasai-Diva-Kalyan section which is the furthest point they operate out of WR. All the WCAM-1's and -2's are homed at Valsad shed in Gujarat.

Many of CR's WCAM-2 locos were not used much in DC zones (exceptions were the CR / Bombay Port Trust's Wadala marshalling yard a portion of which has DC traction, and for hauling the Punjab Mail in the late 1970's) as they delivered very poor performance in DC mode and on CR's heavy grades. Although these locos have the same traction motors as the WAM-4 and WCAM-1, the power output from the WCAM-2 locos is higher than for the WAM-4 and WCAM-1 because in those models the traction motors are underfed (3460kVA transformer in contrast to the 5400kVA transformer for WCAM-2) and do not yield their potential maximum power. Under AC traction, the WCAM-2 locos operate with all six motors in parallel (this has been enforced by modifications to these locos), while in DC mode they also operate in the all-series and series-parallel (2S 3P, i.e., three series-pairs of motors in parallel) configurations.

Recent WCAM-2's from BHEL, including the passenger-specific version WCAM-2P, are rated 2900hp in DC mode and 4700hp in AC mode (max. speed 120km/h in AC mode). These are used by WR for fast trains, running at up to 120km/h on the Virar-Godhra AC section (Mumbai-Virar is DC but has reduced speeds because of the suburban traffic). CR has tried the WCAM-2 and WCAM-2P units but found them usable only with speed restrictions. Some WCAM-2P units have only air brakes.

With the WCAM-2 locos, MU operation is possible with up to 3 (4?) units.

Some (all?) of the WCAM-2 locos were originally leased to IR, ownership remaining with BHEL, the manufacturers.

  • Manufacturers: BHEL
  • Traction Motors: TAO 659 (575kW, 750V). Axle-hung, nose-suspended, force-ventilated.
  • Wheelsets: Trimount fabricated bogies.
  • Transformer: BHEL 5400 kVA.
  • Rectifiers: Two silicon rectifier units D1800N44 (Siemens), 16 cells per bridge. 1000V / 3600A.
  • Gear Ratio: 62:15, 58:21
  • Pantographs: ??
  • Length: 20950mm
  • Total wheelbase: 15698mm
  • Weight: 113t

Comparative Specifications

WCAM–3 WCAM-3These upgraded dual-traction models deliver 4600hp in DC mode and 5000hp in AC mode, and were jointly developed by RDSO and BHEL in 1997. Components are shared with the WCAG-1 locos (see below). Co-Co fabricated bogies (High-Adhesion -- shared with WCAG-1, WAG-7, WDG-2, etc.) with secondary suspension. Monocoque underframe. Air brakes are original equipment. They were originally manufactured under a BOLT (build-own-lease-transfer) contract with BHEL, and are probably still owned by BHEL rather than by IR.

Monocoque underframe. 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. Auxiliaries from Elgi, S F India, Best, Gresham & Craven, etc. Static converter from ACEC for auxiliary supply.

In DC mode, rheostatic braking by self-excitation of traction motors available until 17km/h. Elgi compressor, other auxiliaries from S F India. Rated for 105km/h in both DC and AC mode (sometimes AC mode rated speed is quoted at 110km/h). Traction motor configurations as in the WCAM-1/2 and WAM-4 (all 6 in series, 2S 3P, or all parallel -- the latter is the only one used under AC traction, enforced now by modifications to the locos).

CR uses WCAM-3 locos on Mumbai-Pune and Mumbai-Igatpuri sections which have ghat portions as well as speed restrictions of about 100km/h. Freight rakes double-headed by WCAM-3 (upgraded models) have been sighted on the ghat sections. For excellent WCAM-3 sightings and regular double-header WDM-2 tanker trains, the Kurla-Vidyavihar section is ideal.

MU operation possible with 3 (4?) units.

Some WCAM-3 locos now [2004] are certified only for DC operation for various reasons, although it is possible they will be fixed and returned to full dual-traction service after repairs. As of [12/05], all WCAM-3 locos had been retrofitted with roof-mounted rheostatic braking grids.

  • Manufacturers: BHEL
  • Weight: 121t
  • Traction Motors: Hitachi HS15250A. Axle-hung, nose-suspended, force-ventilated.
  • Transformer:BHEL 5400 kVA. 32 taps.
  • Rectifiers: Two silicon rectifier units D1800N44 (Siemens), 16 cells per bridge. 1000V / 3600A.
  • Gear Ratio: 64:18
  • Pantographs:Stone India, AM-12 (AC), AM-18 B2 (DC)
  • Length: 20950mm
  • Total wheelbase: 15698mm
  • Weight: 113t

Comparative Specifications

More electric (AC) locos on the previous page.

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