Electric Locomotive Classes – AC

Note: Information on the WCM, WCG & WCAM locomotives can be found here.

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

Battery Locomotives

AC Electric Locomotives

WAM–1 Early 2800 hp SNCF design for 25kV AC, with ignitron rectifiers. Introduced in 1959, they were mostly deployed by ER in the Howrah-Asansol-Dhanbad-Mughalsarai section. They were less frequently found 'upstream' in the Delhi-Kanpur-Mughalsarai section, and in the Igatpuri-Bhusaval section of the Central Railway. Mostly used for non-express passenger trains, but some were used double-headed for freight service. Some were still [12/98] in operation on ER (Sealdah-Lalgola passenger, etc.).

WAM-1's are significant in the history of electric traction in India as they were among the first AC electrics to run in India. Like the WAG-1's, some of their advanced features turned out to be unsuitable for Indian conditions.

Manufactured by Kraus-Maffei, Krupp, SFAC, La Brugeoise & Nivelle (50 cycles European group). Ignitron rectifiers feeding four DC traction motors accepting pulsating current input. Motors are connected to the axles by a Jacquemin drive. Speed control by tap-changer on input transformer (motors permanently wired in parallel). Superstructure mounted on bogies with pendular suspension with equalizer beams. Electricals from ACEC, AEG, Alstom, Brown Boveri, Siemens and others. B-B (monomotor bogies). Jeumont transformer (20 taps), Oerlikon exhauster, Arno rotary converter. Air loco brakes, vacuum train brakes.

  • Manufacturers: Kraus-Maffei, Krupp, SFAC, La Brugeoise & Nivelle (50 cycles European group)
  • Traction Motors: Siemens/ACEC/Alstom MG 710A (740hp, 1250V, 480A, 1000 rpm, weight 2750kg). Fully suspended, force-ventilated.
  • Rectifiers: Four water-cooled ignitrons from SGT, each rated for 575kW / 1250V.
  • Pantographs: Two Faiveley AM-12.

Comparative Specifications

WAM–4The problems with the WAM-1 series prompted IR to come up with better models, and after some variations, the WAM-4 model was produced, the first indigenously designed and built electric loco (first units delivered by CLW in 1970-71). They were produced until about 1997.

They use the same Alco asymmetric trimount bogies as the successful WDM-2 diesel class. These locos feature rheostatic braking, and MU capability. They have silicon rectifiers. MU operation up to 4 units possible. Air brakes for loco and vacuum train brakes fitted as original equipment. Rheostatic braking also provided. Speed control by three series-parallel motor combinations and weak field operation. Auxiliaries from Westinghouse and Kirloskar (compressors), S F India (blowers), Northey (exhauster), etc.

This class proved so successful by virtue of its ruggedness suitable for Indian conditions and simplicity of maintenance, that IR used this basic design for a number of other locos later (WCAM-1, WAG-5A, WCG-2, and some WAP models). WAM-4B's were regeared versions for freight use and many were later modified and converted to other classes (See below). WAM-4P locos are intended for passenger operations, with some regearing and usually allowing all-parallel operation of some or all of the traction motors. The WAM-4P loco is still among the most heavily used electric locos of IR. A single WAM-4 can generally haul up to a 24-coach passenger rake.

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. Variants include WAM-4P D (dual brakes), WAM-4P R (??), WAM-4P DB 6P, WAM-4 6P DB HS, and WAM-4 6P D (these are for superfast trains), WAM-4P DB 3P and WAM-4 2S-3P (some superfasts, passengers), and WAM-4P DB 4P (generally for stopping 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 combinatons (three pairs of motors in series, the pairs themselves being in parallel); and further notches with all motors in paralell (at notch 30 all motors are in parallel with resistors dropping out). This is the original configuration of the WCAM-x series of locos too. The WAM-4 locos 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 locos 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 locos to start hauling larger loads without stalling. With increasing use of the WAM-4 locos for passenger traffic the all-parallel configuration was deemed more desirable since it allowed higher speeds and higher acceleration.

Some other odd combinations of these suffixes have been sighted, such as WAM 4+6P+DB+HS and WAM-4 6P-E (?? is this one air-braked or dual-braked?). A goods version of the WAM-4 is classified WAM-4G. WAM-4H is a variant with Hitachi motors. The WAM-4E is purely air-braked. All these locos share bogie design with WCAM-1, WAG-5, WDM-2, and WCG-2 (Alco cast trimount bogie). Although the code indicates a mixed-use loco, most WAM-4's ended up hauling passenger trains. They have been used for regularly hauling freight only in a few locations (Arakkonam - Renigunta, Kirandul-Kottavalasa and other SER sections). Max. speed 110km/h.

[1/05] Most of the WAM-4 locos now have their MU capability disabled as RDSO disapproves of these locos running MU'd over 100km/h.

WAG-5 / WAG-5B locos with road numbers 21101 to 21138 all used to be WAM-4B locos. They were regeared and modified to be suitable for hauling heavier freight loads.

A few WAM-4's have been fitted for OHE monitoring by the Itarsi shed. They have CCTV cameras mounted on top of the headlamp assembly pointing towards the OHE and a separate lamp to illuminate the OHE. Monitors are installed inside the cabs. These locos even have rear view mirrors.

  • Manufacturers: CLW
  • Traction Motors: Alstom TAO 659 A1 (575kW, 750V). 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 locos..
  • Transformer: Heil BOT 3460 A, 22.5kV / 3460kVA.
  • Rectifiers: Two silicon rectifier cells, 1270V / 1000A each cubicle.
  • Pantographs: Two Faiveley AM-12.
  • Axle load: 18.8t
  • Bogies: Alco asymmetric trimount (Co-Co), same as with WDM-2, WDS-6, etc.
  • Hauling capacity: 2010t
  • Current Ratings: (WAM-4 6P) 1100A/10min, 750A continuous

Comparative Specifications

WAP–1WAP1.Photo by PoochiVenkat Built by CLW to RDSO specifications. First in the dedicated electric passenger loco series. Production began in 1980 and the locos were at first used solely for the Howrah-Delhi Rajdhani. A single WAP-1 (#22001) was all that was needed to haul the 18-coach Rajdhani at a max. speed of 120 km/h. and an average speed of around 82km/h. Continuous power 3760hp; starting TE 22.2t, continuous TE 13.8t. Loco weight is 112.8t.

The original WAP-1 locos were modified and regeared versions of the WAM-4, originally classified WAM-4R. Rated max. speed is 130km/h (some documents suggest 140km/h). Some (5?) with Flexicoil Mark II bogies were classified WAP-1 FM II and later WAP-3. Two WAP-1 units were also converted to WAP-6. [10/02] One of them, #22212, the first prototype WAP-6, was then converted to a WAP-4 and was based at Jhansi (now [8/03] at Mughalsarai).

Many remaining WAP-1's are being converted to WAP-4's by a complete retrofit including new traction motors, new transformers, etc. These upgrades do not result in the 'R' suffix in the road number that is typical for rebuilt locos. Ghaziabad shed locos are currently [1/05] the only ones not scheduled for such upgrades and are expected to remain as 'pure' WAP-1 units. The WAP-1E has only air brakes. Earlier WAP-1's had loco air brakes and vacuum train brakes but were retrofitted for dual train brakes. Motors are grouped in 2S-3P combination and weak field operation is available. Elgi compressors, Northey exhausters, S F India blowers. The locos were originally not designed for MU operation but were later modified to allow MU'ing.

  • Manufacturers: CLW
  • Traction Motors: Alstom/CLW - TAO 659 (575kW (770hp), 750V, 1095 rpm) Axle-hung, nose-suspended, force-ventilated.
  • Gear Ratio: 58:21
  • Transformer: BHEL type HETT-3900, 3900 kVA. 32 taps.
  • Rectifiers: Two silicon rectifiers, with S18FN35 cells (by Hind Rectifier) with 64 cells per unit. 2700A/1050V.
  • Axle load: 18.8t.
  • Bogies: Co-Co Flexicoil (cast steel bogies); primary and secondary wheel springs with bolsters
  • Pantographs: Two Faiveley AM-12.
  • Current Ratings: 900A/10min

Comparative Specifications

WAP–4WAP-4Variant of WAP-1 with Hitachi H5 15250 motors (built by CLW), built in 1994 to RDSO specifications. The need to run longer passenger trains (24 to 26 coaches as against the 19-coach capacity of the WAP-1 / WAP-3 locos), and also to eliminate the need for bankers in graded sections (e.g., the busy Itarsi-Nagpur section) led RDSO to consider an upgraded design of the WAP-1 loco and the WAP-4 loco design was published in November 1993. Indigenously designed, higher power rated silicon rectifiers and indigenously-designed 5400kVA transformer. Locomotive reliability is also increased by the use of Hitachi traction motors. Air brakes for loco and train. Different underframe design to handle larger buffing loads. Cast bogie, Flexicoil Mark 1 design. Weight kept to 112t by the use of aluminium plates, thinner underframe, and reducing some components such as sanders. Motors grouped in 6P combination; weak field operation possible.

[2/00] New versions of these with twin-beam headlights, speed recorders and some changes to the control electronics have been rolling out recently [7/00]. WAP-4E are most likely just regular WAP-4 locos from the Vadodara shed. The 'E' suffix is thought to come from the short-lived RDSO directive to denote all air-braked locos and is redundant with the WAP-4 locos (e.g., WAP-1E). WAP-4There is speculation that some of these locomotives may have some additional features such as an electronic sensor for detecting loss of pressure in brake pipes (hence, sometimes the 'E' suffix is explained as 'electronic', although this seems unlikely). More recently [1/05] many of these have been fitted with train-parting / pressure loss alarms, and data recorders for speed, energy consumption, etc. All the new ones have roof mounted twin beam headlights, square WAP-5 type windscreens and a digital notch repeater along with a better layout and good seats for the drivers. Some [12/04] even have windshield washers. A few were provided with signalling lamps on the sides but this does not have seem to have continued with the newer units.

WAP-4[1/03] Although these are officially rated at 140km/h, there are reports that one or more of these have been tested by CLW at up to 169.5km/h.

As of [11/04] this class is still in production at CLW.

Note on the traction motors : The Alstom-designed 770hp TAO motors used in the WAP-1 and WAP-3 were seen as the weak link in the reliability of the locos for passenger train use. At the time, Hitachi motors of 840hp were in use on freight locos and had very high reliability, but adapting them for use with a passenger loco proved a formidable challenge because of the weight constraints. The WAP-4 design efforts involved many modifications for weight reduction, including a lighter underframe, aluminium foil-wound transformer, and the use of aluminium chequered plates, and these have allowed the use of the heavier, but more powerful and more reliable Hitachi motors on the WAP-4 locos.

  • Manufacturers: CLW
  • Traction Motors: Hitachi HS15250 (630kW, 750V, 900A. 895rpm. Weight 3500kg). Axle-hung, nose-suspended, force ventilated, taper roller bearings.
  • Gear Ratio: 23:58 (One loco, #22559, is said to have a 23:59 ratio.)
  • Transformer: 5400kVA, 32 taps
  • Rectifiers: Two silicon rectifiers, (ratings?).
  • Axle load: 18.8t.
  • Bogies: Co-Co Flexicoil Mark 1 cast bogies; primary and secondary wheel springs with bolsters
  • Pantographs: Two Stone India (Calcutta) AM-12.
  • Current Ratings: 1000A/10min, 900A continuous
  • Tractive Effort: 30.8t

A 24-coach (1430t) passenger rake can be accelerated to 110km/h in 338 seconds (over 6.9km) by a WAP-4; to 120km/h in 455 sec. (10.5km); and to 130km/h in 741 sec. (20.5km).

Comparative Specifications

WAP–5 WAP5.Photo by Vivek ManviThis class started with a batch of 10 locos (#30000-30010, skipping #30008) imported from ABB / AdTranz in 1995 (Actually 11 were imported but one (#30008) was damaged by fire in transit and deemed unusable on arrival. It was then used as a bank of spare parts for the others.) These are among the few currently [5/99] with IR to have an advanced design with GTO thyristor converters and 3-phase asynchronous motors. CLW has been manufacturing the motors since Feb. 24, 2000. Rated top speed is 160km/h, although in trials a WAP-5 loco is said to have been run at 184km/h. Continuous power at wheel rim is 4000kW (5450hp). A WAP-5 can take a 24-coach passenger train to 110km/h in 324 seconds. Wheel arrangement is Bo-Bo. Auxiliaries from ABB, Howden Safanco, BEHR, etc. [1/03] Although these are officially rated at 160km/h, one of these has been tested by CLW at up to 184km/h. These locos are intended for use with high-speed medium load trains such as the Rajdhani and Shatabdi trains, in contrast to the WAP-7 (see below) which is more powerful but which is intended for lower-speed haulage of heavier trains.

Other notable features of this loco are the provision of taps from the main loco transformers for hotel load, pantry loads, flexible gear coupling, wheel-mounted disc brakes, and a potential for speed enhancement to 200km/h. 78t weight. Braking systems include regenerative braking (160kN), loco disc brakes, automatic train air brakes, and a charged spring parking brake. MU operation possible with a maximum of two locos.

[2/00] Currently, [9/03] four indigenous WAP-5's from CLW (first one built May 17, 2000) with somewhat different contours, and electricals from BHEL, are homed at Ghaziabad shed. (#30011 'Navodit', #30012, 'Navajagaran', #30013 'Navakriti', and #30014).

Being homed at sheds in the north, they are understandably in use for northern routes, but recently [12/01] some have been spotted regularly as far south as Chennai. In 2000, plans were announced for variants with 6000hp power and 200km/h capability to be manufactured, but nothing has been heard since on that front. After the first four were built by CLW, there seems to have been a pause in the manufacture of this class at CLW, and as of [11/04], more were expected to be produced but it was not known when production would resume. A problem with the Hurth coupling and its indigenous replacement seem to have been part of the delay, but the locally manufactured components have now [12/04] passed trials.

Air-conditioning: The original design called for these locos to have air-conditioned cabs. This, however, has been dogged by controversy over costs and fitment, and the first units made by CLW do not have air-conditioned cabs. One of the ABB units, #30000, does have air-conditioning, fitted by the Ghaziabad shed as an experiment. The Ghaziabad shed may be planning to retrofit some of its other WAP-5 locos with air-conditioning.

  • Manufacturers: ABB / CLW
  • Traction Motors: ABB's 6FXA 7059 3-phase squirrel cage induction motors (1150kW, 2180V, 370/450A, 1583/3147 rpm) Weight 2050kg. Forced-air ventilation, fully suspended. Torque 6930/10000Nm. 96% efficiency.
  • Gear Ratio: 67:35:17. (3-stage gears)
  • Transformer: ABB's LOT-7500. 7475kVA primary, 4x1450kVA secondary.
  • Power Drive: Power convertor from ABB, type UW-2423-2810 with SG 3000G X H24 GTO thyristors (D 921S45 T diodes), 14 thyristors per unit (two units). Line convertor rated at 2 x 1269V @ 50Hz, with DC link voltage of 2180V. Drive convertor rated at 2180V phase to phase, 953A output current per phase, motor frequency from 0 to 160Hz.
  • Axle load: 19.5t
  • Bogies: Bo-Bo Henschel Flexifloat; bogie centre distance 10200mm; bogie wheel base 2800mm
  • Unsprung mass per axle: 2.69t
  • Pantographs: Two Stone India (Calcutta) AN-12.
  • Wheel diameter: 1092mm new, 1016mm worn
  • Wheel base: 13000mm
  • Length over buffers: 18162mm
  • Length over headstocks: 19280mm
  • Body width: 3142mmn
  • Cab length: 2434mm
  • Pantograph locked down height: 4537mm
  • Tractive Effort: 26.3t

A 24-coach (1430t) passenger rake can be accelerated to 110km/h in 312 seconds (over 6km) by a WAP-5; to 120km/h in 402 sec. (6.9km); and to 130km/h in 556 sec. (14.2km).

Comparative Specifications

WAP–6WAP-6[12/08] All locos in the class have been converted to WAP-4. This class was really a variant of the WAP-4 design. One or two prototypes were built early from existing WAP-1 or WAP-4 locos without renumbering. WAP-4 #22212 (formerly a WAP-1) was the first to be converted to a WAP-6; it was provided with Flexicoil bogies and other upgrades. Later this particular loco was later converted back to a WAP-4 (and even refitted with the standard WAP-4 bogies). Curiously, it spent a long time with both class codes WAP-4 and WAP-6 on it. Later, more WAP-1 locos were regeared and provided with high-adhesion fabricated bogies (Flexicoil Mark IV) which are somewhat similar to the Alco Hi-Adhesion bogies. About 16 (perhaps more) of these were built (All in the number series 22400-22416.) Of railfan interest is the fact that some of them reveal their origins in the form of the old WAP-4 class code being still evident -- often a '6' is crudely repainted over the '4' which is still visible.

They were intended for service at 160km/h but failed trials and were restricted to a top speed of 105km/h. They were then used for less prestigious trains such as the Amritsar Exp., Doon Exp., or Janata Expresses.

The remaining ones (thought to be 13 in number) are now [4/02] homed at Asansol. It is reported [5/02] that some of these (perhaps only two, #22406, #22408) have been upgraded with better wheelsets, etc., so that they are now capable of higher speeds (max. 160km/h?). [1/05]One loco #22410 looks to have been converted to a WAP-4 and is now homed at Howrah. Air brakes for loco and train provided as original equipment. Auxiliaries from Best & Crommpton, S F India, Accel/Flakt, Elgi, etc

It appears that the WAP-6 were a failed experiment in upgrading the basic WAP design using different Flexicoil bogies and other changes.. When the performance of these units proved unsatisfactory, IR switched to improving the WAP-4 loco and stuck to that design instead.

  • Manufacturers: CLW
  • Traction Motors: Hitachi HS15250 (See description under WAP-4.) Axle-hung, nose-suspended, force-ventilated.
  • Gear Ratio: 58:23
  • Transformer: CCL make, aluminium coil. 5400kVA. 32 taps.
  • Rectifiers: Two silicon rectifier cubicles. 2700A/1050V.
  • Axle load: 18.8t.
  • Bogies: Fabricated Flexicoil Mark IV bogies.

Comparative Specifications

WAP–7WAP-7[11/00] Identical to WAG-9 (see below) with modified gear ratio (72:20) and application software. 140km/h (130km/h?) top speed. 6125hp max. power; 6000hp continuous at wheel rim. At 123t, it is much heavier than the 78t WAP-5. Intended to haul heavier, 26-coach passenger trains and passenger/parcel mixed trains. The first one, Navkiran, #30201, which was commissioned in 2000, is homed at Gomoh although it has been seen [8/00] at Ghaziabad as well.

Initial models were rated at 6125hp total power and 33000 kgf (323kN) tractive effort. Modifications during continuing trials resulted in improved performance with the loco now yielding 6350hp total power and 36000 kgf (352.8kN) tractive effort. In the trial runs [7/02] the upgraded WAP-7 #30203 was shown able to take a 24-coach train to 110km/h in just 235 to 245 seconds (compare: 324 seconds for a WAP-5). Braking systems as in the WAP-5, with regenerative braking rated at 183kN in the first units and 260kN in the later ones.

Earlier trials with WAP-7 locos had yielded times around 390 seconds for the same test, which had cast doubts on the future of this loco class which was designed to perform better than the WAP-5. After some trials with the Prayagraj Exp. in early 2002, now [11/02] the WAP-7 is being used to haul the 24-coach rake of ER's Poorva Exp. and will presumably soon be used for other trains as well. Max. tested speed is 160km/h, rated for 140km/h.

Better performing variants of the WAP-7 have been under development [9/04]; changes are said to include higher capacity components (including the main transformer) to allow stall-free running on 1:100 gradients, and a higher tractive effort of 42000 kgf (411kN). Some of the units starting around #30212 are also thought to have some enhancements in comparison to the very first ones. [11/04] Other plans by CLW for this loco class are said to include the provision of IGBT control, greater automation of some control tasks, and in-cab signalling. MU operation possible with a maximum of two locos.

The WAP-7 appears to have returned to the older (WAM, earlier WAP) style of pantograph with a single collector bar instead of the double collector bar used for the WAG-9.

  • Manufacturers: CLW
  • Traction Motors: 6FRA 6068 3-phase squirrel-cage induction motors (850kW, 2180V, 1283/2484 rpm, 270/310A. Weight 2100kg, forced-air ventilation, axle-hung, nose-suspended. Torque 6330/7140Nm. 95% efficiency.)
  • Gear Ratio: 72:20
  • Axle load: 20.5t
  • Wheel diameter: 1092mm new, 1016mm worn
  • Wheel base: 15700mm
  • Bogies: Co-Co, ABB bogies; bogie wheel base 1850mm + 1850mm
  • Unsprung mass per axle: 3.984t
  • Length over buffers: 20562mm
  • Length over headstocks: 19280mm
  • Body width: 3152mmn
  • Cab length: 2434mm
  • Pantograph locked down height: 4525mm
  • Tractive Effort: 36.0t

A 24-coach (1430t) passenger rake can be accelerated to 110km/h in 240 seconds (over 4.7km) by a WAP-7; to 120km/h in 304 sec. (6.7km); and to 130km/h in 394 sec. (9.9km).

Comparative Specifications

WAG–1WAG-1Among the first AC electrics to run in India. Early ones were imported from European manufacturers (1963). The first one built in India was named 'Bidhaan' (Nov. 16, 1963).

Typically French features include elongated 'D'-shaped buffers. The Indian modifications included addition of a cowcatcher, CBC couplers, and a large roof-mounted searchlight-style head lamp. Although sterling performers, some of their highly advanced features such as the spring-borne traction motors, etc., did not suit Indian conditions.

They had monomotor bogies with B-B wheel arrangements, Jacquemin drives (?), and excitron rectifiers. Air brakes for loco, vacuum train brakes as original equipment. Regenerative braking provided. MU operation up to 4 units. Motors are permanently connected in parallel; speed control by transformer taps.

Several were based at Arakkonam, Vijayawada, and other places. Most were decommissioned by the 1990s, although a few were seen still in use in 2000 or so (Godhra, Renigunta-Gudur, etc.). None were known to be in use after 2002.

Two units (the last ones) built by CLW in 1964 are sometimes denoted WAG-1S; it is not clear how they are different from the others.

  • Traction Motors: AEC/Alstom/Siemens MG1420. Two motors (monomotor bogies), force-ventilated, fully suspended.
  • Gear Ratio: 3.95:1
  • Transformer: MFO, type BOT 3150. 22.5kV / 3000kVA. 32 taps.
  • Rectifiers: Secheron A268 Excitrons (four). 510A / 1250V.
  • Axle load: 21.3t
  • Max. Haulage: 1820t
  • Pantographs: Two Faiveley AM-12

Comparative Specifications

WAG–5WAG-5Introduced in 1984. Power 3850hp (some documents say 3900hp, which may be a later modification), 6-axled (Co-Co). Starting TE 382kN (33500kgf); continuous TE 202kN (20600kgf). Adhesion 29%. A very successful class, and probably the one with the most numbers produced. There are many variants of these, starting with the plain WAG-5. WAG-5A locos have Alsthom motors. Later versions were WAG-5H and variants with Hitachi motors: WAG-5HA by CLW, with high-adhesion bogies, and WAG-5HB WAG-5HBbuilt by BHEL to RDSO's specifications. (Note: Lallaguda shed uses the simple code 'WAG-5' for locos that would normally be denoted 'WAG-5HA'.) [4/02] Newer versions have been spotted: WAG-5HG, WAG-5HR, WAG-5RH (here the 'R' is believed to denote rheostatic braking, but not all WAG-5 class locos that have rheostatic braking use this suffix), WAG-5D, WAG-5P for fast passenger traffic (mail and express trains) with gear ratio 21:85. etc,. WAG-5HE variants are believed to have Hitachi traction motors and only air brakes.

The detailed differences among these variants are not precisely known. Specifications for the base WAG-5 model are given below. Some of the variants are known to have different gearing and equipment, and different rated speeds. The original WAG-5 units had a top speed of 80km/h. Many variants have a gear ratio of 21:58, the same as that of the WAM-4 6P, which allows these WAG-5 locos to be used for mixed applications including hauling passenger trains at 100km/h.

Auxiliaries are from many sources: typically Elgi compressors, Northey exhausters, and other equipment from S F India, but many variations exist. Speed control by parallel combinations of motors and weak field operation. Air brakes for loco, dual train brakes are original equipment.

Although a great improvement over earlier locomotive classes, the WAG-5 models do have limitations, one of which is the inability to start and haul large loads (4700t -- 58 BOXN wagons) on gradients steeper than 1:200 or so.WAG-5 locos can be used as multiple units in configurations of 2, 3, 4, or more locos.

With the large influx of WAG-7 and WAG-9 locos in recent years, many WAG-5 locos are now also being put to use hauling local passenger trains. Some such as the WAG-5E loco #23989 'Krishnaveni' (of Vijayawada [1/04]) have also been modified for this purpose in their interior equipment as well as some of the exterior aspects. For some reason, the BHEL-built WAG-5HA / 5HB locos are never seen used with passenger trains. All of the WAG-5HB units are at Jhansi near BHEL's own installations so that BHEL can handle their maintenance.

The WAG-5B locos are converted WAM-4 units. These have road numbers in the range - 21101 to 21138. This is believed to have stemmed from a decision to have a separate line of freight loco models based on the highly versatile and successful WAM-4 family of locos.

In the external appearance of WAG-5 locos, it can be seen that locomotives with road numbers up until 23293 have side louvres and round glass windows like the WAM-4 locos showing the legacy of the WAM-4 design. From number 23294 onwards the locos have the newer WAP-4/WAG-7 style of louvres, thought to be for better ventilation.

More recently WAG-5 locos of all types have been retrofitted with data loggers, flasher lights, train parting alarms, etc.

WAG-5 #23026, homed at Bhusawal, was selected for a trial project by the RDSO to develop designs for adoption of thyristor controlled electricals for the tap changer based locomotives in 1995. The project was began in 1992 because there was an increasing dearth of suppliers for the tap changer control, it was inefficient and so the new system, promising better performance, was to be retrofitted after trials into all the older locos. A prototype system, developed in collaboration with Bhabha Atomic Research Centre, was fitted in this locomotive and trials were carried out between 1997 and 1998. However, due to several problems, the biggest of which was intereference caused with signalling equipment, the project was dropped in 1999. The loco was then refitted with the standard equipment and brought into service as a WAG-5P which it is till this date [1/05].

  • Traction Motors: Alstom TAO 659 (575kW, 750V, 1070 rpm) or TAO 656; or Hitachi HS 15250A (See description under WAP-4.) Axle-hung, nose-suspended. Six motors.
  • Gear Ratio: 62:16 or 62:15 with Alstom motors, some 64:18 (Hitachi motors), many now 58:21 for mixed use.
  • Transformer: BHEL, type HETT-3900. 3900kVA, 22.5kV, 182A. 32 taps.
  • Rectifiers: Silicon rectifiers (two) using 64 S-18FN-350 diodes each from Hind Rectifier. 2700A / 1050V per cubicle.
  • Bogies: Co-Co cast bogies (Alco asymmetric trimount -- shared with WDM-2, WAM-4).
  • Axle load: 20t
  • Max. Haulage: 2375t
  • Pantographs: Two Faiveley AM-12
  • Current Ratings: 1100A/10min, 750A continuous

Comparative Specifications

WAG–6WAG-6A.Photo by Dr.MSM Saifullah WAG-6A models are from ASEA (bodies by SGP in Austria and transported to ASEA, Västerås, Sweden on freight wagon type bogies. Trivia: The second body (26001) passed Malmö in southern Sweden on 1987-09-01). ASEA had a specially constructed piece of 1.676m Indian broad-gauge line to allow testing of the locomotives before delivery. Delivery was to Göteborg harbour on standard-gauge bogies, where they were fitted with broad-gauge bogies before they were placed on board. The first shipping was planned to begin December 1987 with another batch in January 1988, although the actual shipping dates were probably later. The WAG-6B and WAG-6C models are from Hitachi. They are all 6000hp locos with thyristor-controlled DC traction motors. Until about 1993 they were the most powerful freight locos in IR's fleet. The development of this technology (chopper control) stopped when the (better) AC motor technology was introduced in IR in the form of the WAP-5 and WAG-9 locomotives.

Six bogie-mounted separately excited DC traction motors are used, and speed control is via the manipulation of the phase angle by a thyristor converter and a separately powered field coil. Microprocessor control with ground speed detection (slip control) and creep control system to maximize adhesion. Air brakes for loco and train; dynamic brakes provided. WAG-6A and WAG-6B locos have Bo-Bo-Bo wheel arrangements, whereas the WAG-6C locos have a Co-Co arrangement. The WAG-6 series locos are the only ones with 'vestibules' to connect between MU'd locos. WAG-6A locos have half-height vestibules and WAG-6B and WAG-6C locos have full-height vestibules.

The WAG-6A body shells were built by SGP in Austria; the rest of the locos were built and the entire units assembled in Västerås, Sweden by ASEA. ASEA constructed a special length of 1.67m (BG) track for testing these before delivery. The locos were fitted with BG bogies at Göteborg harbour after being transported there on standard gauge bogies. The first WAG-6A was delivered around December 1987 and the remaining five in January 1988.

WAG-6B.Photo by Dr.MSM SaifullahAll WAG-6 locos were (are [1/04]) at Waltair (Vishakhapatnam) and have generally been used for ore freights and material trains on the Kirandul-Kottavalasa line. Until about 1999 or 2000, they were in regular service, although maintenance problems began affecting their service from about 1997. Later, repeated problems have been experienced with the unavailability of spare parts which kept them from getting needed periodic overhauls. In Oct. 2002 the WAG-6A were technically suspended from operations for POH for a while. Most of the WAG-6B and WAG-6C were also similarly suspended at different times.

However, many of them still labour on – see below. Spare parts have since been ordered for them [12/03] as special case procurement in some cases, and indigenous manufacturers have been invited to duplicate parts that are no longer available from the original manufacturers. In some cases parts are cannibalized from one loco for another. A particular electronic card for the on-board computer is said to be [1/04] in severe short supply and unavailable from ABB and Hitachi; ECIL and DRDO are attempting to duplicate them. It is alleged that these locos were procured by the Railway Ministry without consultation with RDSO, hence the problems with maintenance and spares. For political reasons, it is also considered not feasible to simply scrap these locos right away.

Status [1/04] WAG-6A locos #26000, #26001, #26002 and #26005 were in working order and used on the KK line. #26003 and #26004 were awaiting POH. WAG-6B locos #26010, #26011, #26012 and #26013 were under POH. #26010 went on a trial run to S. Kota and returned with some minor problems but will be ready to re-enter service MU'd with #26011 which is almost ready. WAG-6B locos #26014 and #26015 were waiting their turn for POH. Of the WAG-6C locos, all six (#26020 - #26025) were in regular use on the KK line; one or two of them have shown issues with wheel slip.

Status [8/05] Of 18 locomotives, 14 are said to be in service, 2 getting their POH, and 2 are out of service awaiting POH.

The WAG-6A models are said to be upgradable to 160km/h but IR never tried this out. All WAG-6 variants can be used in MU pairs but not with more than 2 locos.

  • Traction Motors: ASEA make (WAG-6A), L3 M 450-2. Six motors, fully suspended, force-ventilated, separately excited, 3100kg ; (WAG-6B) Hitachi HS 15556-OIR, bogie mounted, force-ventilated, compound-wound, 3200kg ; (WAG-6C) Hitachi HS 15256-UIR, axle-hung nose-suspended, force-ventilated, compound-wound, 3650kg.
  • Transformer: (WAG-6A) ASEA: TMZ 21, 7533kVA; (WAG-6B/C) Hitachi AFIC-MS, 6325kVA.
  • Thyristor controller: (WAG-6A) 24 YST 45-26P24C thyristors each with 24 YSD35-OIP26 diodes, 2x511V, 2x4500A; (WAG-6B/C) 32 CGOIDA thyristors each with 24 DSP2500A diodes. 2x720A, 850V.
  • Pantographs: (WAG-6A) Two Stemman BS 95; (WAG-6B/C) Two Faiveley LV2600

Comparative Specifications

WAG–7WAG-7Built by CLW to RDSO specifications, these represent the next indigenous design step up from the WAG-5 locomotives. Used primarily for goods haulage, these locos have a Co-Co wheel arrangement with high-adhesion bogies (shared with WCAG-1, WCAM-3, WDG-2/3A) and Hitachi motors providing 5000hp. Starting TE 402kN (41000kgf); continuous TE 235kN (24000kgf). Adhesion 34.5%. The higher tractive effort compared to the WAG-5 locos allows them to attain higher balancing speeds under load. The first 71 of these all went to the Mughalsarai shed. Kanpur was the second shed to get these locos.

Traction motors are permanently coupled in parallel and speed control is through the use of transformer taps. Max. speed is 100km/h. Air brakes and dynamic (rheostatic) brakes for loco, dual train brakes. MU operation with up to 4 units is possible. Traction equipment such as the smoothing reactor, etc., are all higher rated than in the WAG-5 due to the higher currents this loco draws. Auxiliaries include Rigi compressor, Arno rotary converters, Siemens smoothing reactor, Northey exhauster; other auxiliaries such as blowers from S F India. A number of these locos have been retrofitted with static converters to power the auxiliaries, replacing the older Arno rotary converters. These static converters are more efficient and require less maintenance, besides having self-diagnostic systems to make troubleshooting easier.

WAG-7These locos too, have limitations similar to the WAG-5 in not being able to start and haul 4500-4700t loads on gradients steeper than 1:200. When they were being designed and introduced, experiments were carried out to vary the gear ratio. The high-adhesion bogies also underwent some modifications for reduction of weight transfer.

The WAG-7H designation is applied to two locomotives of the WAG-7 class that were experimentally modified to provide higher TE by increasing their weight. Oscillation trials were conducted on a ballasted WAG-7 (#27002) around 1995, and then a new WAG-7 loco was built by CLW to have higher weight using thicker plates in the underframe of the loco (#27061, 1995). Weight is 132t, max. TE 441kN (45000 kgf). Traction motors are Hitachi HS15250-G, perhaps a minor variant of HS15250.

[4/04] Newer WAG-7's have been spotted (e.g., #27455 'Samrat') that externally look somewhat like a WAG-9 and with several improvements such as closed-circuit cameras for monitoring the pantograph and GR, a spotlight to illuminate the pantograph at night, large green lamps to exchange signals on the run, fog lamps, and single-piece windshield. New Katni shed is especially known to add the OHE monitoring equipment to WAG-7 locos. Cabs of some units are air-conditioned. Newer batches of WAG-7's [12/04] also have data loggers and train parting alarms (based on sensors for detecting loss of brake pressure), as standard equipment. They are also said to have 'microprocessor control' although it is not clear what this implies.

  • Traction Motors: Hitachi HS15250-G (a variant of the standard HS15250 with higher current rating (thicker wire gauge, better insulation); see description under WAP-4.) Motors built by CLW and BHEL.
  • Gear Ratio: 65:18 (65:16?)
  • Transformer: CCL India, type CGTT-5400, 5400kVA, 32 taps.
  • Rectifiers: Two silicon rectifiers, cell type S18FN350 (from Hind Rectifier), 64 per bridge, 2700A / 1050V per cubicle.
  • Axle load: 20.5t
  • Bogies: Alco High-Adhesion bogies, fabricated bogie frame assembly, with unidirectional mounting of traction motors, primary and secondary suspension.
  • Hauling Capacity: 3010t
  • Pantographs: Two Stone India (Calcutta) type AN-12.
  • Current Ratings: 1350A/2min, 1200A/10min, 960A/hr, 900A continuous

Comparative Specifications

WAG–9WAG-9These are essentially the same as the WAP-7 units, with some differences in gearing and the control software to make them suitable for freight operations. The first few were imported from ABB (6 fully assembled and 16 in kit form (7 completely knocked down, the rest partially assembled), in 1996). These are numbered 31000 to 31021.

In November 1998, CLW started producing these with indigenous components. The first one, 'Navyug' (translated, 'New Era'), was flagged off on Nov. 14. They have (like the WAP-5 units) GTO thyristor converters and 3-phase asynchronous motors.

Manufacture of the traction motors at CLW started on Jan. 11, 1999. Rated at 6125hp each, two units can haul 4500t trains on gradients of 1:60. A single unit can start a 4700t load (58 BOXN wagons) on a gradient of 1:180 (some CLW documents say 1:150), a great improvement over the WAG-5/WAG-7 locos that were restricted to hauling such loads in sections of gradients 1:200 or less (this was the primary motivation behind the induction of the 3-phase technology for freight locos). Total weight 123t. Continuous power at wheel rims 4500kW (6000hp). Starting TE 520kN; continuous TE 325kN.

They also generally have better adhesion than the WAG-5/WAG-7 locos, partly because of the computerized slip control. Rated top speed is 100km/h. Axles Co-Co. Pantograph has a double collector bar in the Adtranz-built units; the CLW-built units use a pantograph with a single collector pan, as in other AC electrics. Multiple unit operation possible; although the locomotive designs provide for several units to be MU'd together, IR restricts these to just two units being coupled at a time because of dynamic loading restrictions on most bridges.

Auxiliaries from ABB, Landert, Behr, Howden Safanco, etc. Regenerative brakes provide about 260kN of braking effort.

[7/02] So far about 49 are in service (22 imported as mentioned above, the rest from CLW). One (#31008) was damaged by fire while working a train on NR.

  • Manufacturers: ABB, CLW
  • Traction Motors: ABB's 6FRA 6068 (850kW, 2180V, 1283/2484 rpm, 270/310A. Weight 2100kg) Axle-hung, nose-suspended.
  • Gear Ratio: 77:15 / 64:18
  • Transformer: ABB's LOT 6500, 4x1450kVA.
  • Power Drive: Power convertor from ABB, type UW-2423-2810 with SG 3000G X H24 GTO thyristors (D 921S45 T diodes), 14 thyristors per unit (two units). Line convertor rated at 2 x 1269V @ 50Hz, with DC link voltage of 2800V. Motor/drive convertor rated at 2180V phase to phase, 971A output current per phase, motor frequency from 0 to 132Hz.
  • Hauling capacity: 4250t
  • Bogies: Co-Co, ABB bogies; bogie wheel base 1850mm + 1850mm
  • Wheel base: 15700mm
  • Axle load: 20.5t
  • Unsprung mass per axle: 3.984t
  • Length over buffers: 20562mm
  • Length over headstocks: 19280mm
  • Body width: 3152mmn
  • Cab length: 2434mm
  • Pantographs: Two Secheron ES10 1Q3-2500.
  • Pantograph locked down height: 4525mm

Comparative Specifications

WAG–9HWAG-9HA heavier variant of the WAG-9 (12t extra ballast, welded at four locations in the machine room behind the cabs -- a design proposed by CLW and approved by AdTranz) and consequently higher TE. Everything else was just as in the WAG-9 class, except for some application software changes. This was expected to be used in haul heavy freights (58 BOXN wagons, 4700t) without the need for multiple units even on incline sections of 1:150. The ballasting raised the starting TE from 460kN to 520kN. Continuous TE 325kN. The first (and only, as it turned out) of this class was was commissioned on June 30, 2000. This locomotive, #30130, 'Navshakti', then homed at Gomoh, cleared trials but because of concerns about the weight, did not enter regular service. It was deballasted and converted to a plain WAG-9 by mid-2002. That was the only unit of this class ever tried out. The class was intended for MU operation (2 units). Trivia: This reclassified loco, now [11/04] at the Ajni shed, still sports its variant livery with two white stripes instead of the single yellow stripe characteristic of other WAG-9 locos.

  • Manufacturers: ABB, CLW
  • Traction Motors: ABB's 6FRA 6068 3-phase squirrel-cage induction motors (850kW, 2180V, 1283/2484 rpm, 270/310A. Weight 2100kg) Axle-hung, nose-suspended.
  • Gear Ratio: 77:15 / 64:18
  • Transformer: ABB's LOT 6500, 4x1450kVA.
  • Power Drive: Power convertor from ABB, type UW-2423-2810 with SG 3000G X H24 GTO thyristors (D 921S45 T diodes), 14 thyristors per unit (two units). Line convertor rated at 2 x 1269V @ 50Hz, with DC link voltage of 2800V. Motor/drive convertor rated at 2180V phase to phase, 971A output current per phase, motor frequency from 0 to 132Hz.
  • Axle load: 22.5t
  • Hauling capacity: 4700t
  • Bogies:Co-Co
  • Pantographs: Two Secheron ES10 1Q3-2500.

More electric (DC and Bi-current AC/DC) locos on the next page.

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