The Indian locomotive class WDG-3A is a class of diesel–electric locomotive that was developed in 1994 by Banaras Locomotive Works (BLW),Varanasi for Indian Railways. The model name stands for broad-gauge (W), Diesel (D), Goods traffic (G) engine, 3,100 hp (3A) locomotive. They entered service on 18 July 1995. A total of 1,164 WDG-3A units were built between 1994 and 2015 at BLW, Varanasi with a few units being produced by Diesel Loco Modernisation Works (DLMW) and Parel Workshop.

It is the dedicated freight version of the WDM-2 and shares the same engine and horsepower with WDM-3A. It is a locomotive class train with high reliability and few maintenance problems usually. Due to the introduction of more modern locomotives like WDG-4 and electric trains, a significant number of locomotives have been withdrawn from use and scrapped. Yet a good number of WGD-3As are active on the mainline railway and for other services.

, 375 locomotives still retain "operational status" on the mainline as WDG-3A, with a few examples having been converted to WAGC-3 or WAG-10.

History

The first units of this class was delivered on July 18, 1995, under the name of WDG-2. The class was manufactured till end of 2015. All the older locomotives built by DLW had regular WDM-2 type square short hood profile and control stand position and the locomotives are rated at 3,100 HP.

From 2009 onward, they are equipped with Daulat Ram DBR, microprocessor control and an Auxiliary Power Unit (APU) in the short hood thus they bear external resemblance to the WDM-3D class. The WDG-3A has a higher tractive effort (7.5 t more) and axle load (1.7 t) compared to the WDM3A despite having the same engine and horsepower rating. Many units of this class has been named "Shakti" and can easily be recognized by their orange livery with cream stripe and lightning bolts. Besides Indian Railways, WDG-3A are being use by private companies for industrial uses, thermal power plants, port trusts, etc.

Production was stopped in 2015 when advanced locomotives like the WDG-4D were built, thus rendering the ALCO platform obsolete. Two WDG-4s can haul more goods than three WDG-3A combined. Meanwhile, Diesel Loco Works in Varanasi rebuilt few of the existing locomotives that had reached midlife into a purely electric twin section 10,000 hp (7,457 kW) locomotive, classifying them as the WAG-C3/WAG-10.

Sub Classes

WDG-3B They were an experimental technical variant of the WDG3A with an upgraded ALCO engine to output 3,200 hp, though it was unsuccessful, and all units were reverted to normal WDG-3A. One of the locomotives of this class was numbered #14796.

WDG-3C Another experimental class, but this time rated at 3300 hp. Only one unit (#14962) was produced and was painted in a unique "Dark Rose/Cheetah" livery. This loco was derated to 2,600 hp, but is still with the Katni diesel locomotive shed. This class was unsuccessful as well.

WDG-3D Freight version of the WDM-3D. Only one (#13301) unit was marked with this marking. It may possibly be rated at 3400 hp. Now it has been derated to 2600 hp with WDG-3A class markings and homed at the Vatva Loco Shed.

Locomotive sheds Zone Name Shed Code QuantityCentral Railway Pune PADX 15 Kalyan KYDX 10 Kurla CLAD 23Eastern Railway Andal UDLD 4 Jamalpur JMPD 40East Central Railway Pt. Deendayal Upadhyaya DDUX 9Samastipur SPJD 17Northern Railway Ludhiana LDHD 48 Lucknow AMVD 25 Tughlakabad TKDD 10 North Central Railway Jhansi JHSD 18 North Eastern Railway Izzatnagar IZND 1 North Western Railway Abu Road ABRD 9Southern RailwayErnakulam ERSX 7 Golden Rock GOCD 8 Tondiarpet TNPD 9South Central Railway Moula Ali MLYD 5South Coast Railway zoneVisakhapatnam WATD 1 Gooty GYD1South Eastern Railway Bondamunda BNDX 20 South East Central Railway Raipur RPDX 34 South Western Railway Krishnarajapuram KJMD 1Western Railway Ratlam RTMD 30 Sabarmati SBTD 22 West Central Railway New Katni Jn. NKJD 8Total Locomotives Active as of September 2026 375

Technical specifications Technical details are as follows: Manufacturers DLW Engine Alco 251-C, 16 cylinder, , ( site rating, earlier ) with Napier NA2951R/ ABB VTC-304-VG15/ GE 7s 1716 turbo supercharged engine. 1,050 rpm max, 400 rpm idle; bore x stroke; compression ratio 12.5:1. Direct fuel injection, centrifugal pump cooling system ( at 1,050 rpm), fan driven by eddy current clutch ( at 1,050 rpm) Governor EDC / Woodward 8574-650TransmissionElectric, with BHEL TA 10102 CW alternator (1,050 rpm, 1,100 V, 4,400 amperes) (Earlier used BHEL TG 10931 AZ alternator)Traction motorsBHEL TM 4906 AZ/ 4907 BZ () (with roller bearings)Axle load, total weight BogiesAlco High Adhesion Fabricated BogiesStarting TE at adhesion 30.8%, continuous Length over buffer beamsDistance between bogies

See also Indian locomotive class WDM-3A Indian locomotive class WDM-2 List of diesel locomotives of India Indian Railways Rail transport in India

References