| WDS-6 | |
| Powertype: | Diesel |
| Builder: | BLW, Central Railway Loco Workshop, Parel |
| Builddate: | 1975+ |
| Totalproduction: | WDS-6: 300 WDS-6AD: 111 |
| Rebuilder: | Parel Workshops |
| Britishclass: | Co-Co |
| Uicclass: | Co′Co′ |
| Bogies: | ALCO Asymmetric cast frame trimount |
| Wheeldiameter: | 10920NaN0 |
| Wheelbase: | 12.834abbr=onNaNabbr=on |
| Length: | 16.088abbr=onNaNabbr=on |
| Width: | 2.864abbr=onNaNabbr=on |
| Height: | 4.185abbr=onNaNabbr=on |
| Axleload: | 21000kg (46,000lb) |
| Locoweight: | 113000kg (249,000lb) |
| Fueltype: | Diesel |
| Fuelcap: | 3000L |
| Lubecap: | 530L, 630L DLW |
| Watercap: | 22L, 28L DLW |
| Primemover: | ALCO 251-D |
| Rpmrange: | 400-1100 |
| Enginetype: | Inline, 6-cylinder, diesel |
| Aspiration: | Turbo-supercharged |
| Displacement: | 267 mm |
| Generator: | DC |
| Tractionmotors: | 6 DC |
| Cylindercount: | 6 |
| Multipleworking: | 2 |
| Maxspeed: | 71km/h |
| Poweroutput: | Max:1400HP Site rated:1300HP |
| Tractiveeffort: | 34t maximum 16.05t continuous |
| Locobrakes: | 28LV-1, Air brake for Locomotive using SA-9 brake handle |
| Locale: | All over Indian Railways, also leased and sold to some private- and public-sector industrial concerns |
| Currentowner: | Indian Railways, private industries |
| Disposition: | Active |
The Indian locomotive class WDS-6 is a diesel–electric locomotive used by the Indian Railways mainly for shunting and also for performing departmental duties. The model name stands for broad gauge (W), Diesel (D), Shunting (S) engine, 6th generation (6). As of April 2022, 375 units of this class are currently in use all over India.
This class was designed in 1975 to address the need for a powerful shunting locomotive with the ability to haul 20- to 24-coach rakes. The previous WDS-4 class was found to be grossly underpowered for this kind of operation. A WDS-6 locomotive basically consists of a YDM-4 powerpack (a 6-cylinder, 4-stroke, inline, turbo-supercharged ALCo engine) mounted on a WDM-2 body frame. Beginning in 1975, these were initially manufactured solely by BLW, Varanasi, but later, the Parel Workshop started building them using CKD (completely-knocked-down) kits provided by DLW.WDS-6 units can be easily recognized by their low short hoods (with two cab windows above these) and flat-ended cabs on the long-hood end. Many of them were sold and transferred to private industrial concerns and public sector undertakings (PSUs) in huge numbers, but still display their IR road numbers.
Total Locomotives active as of April 2024 : 192
| Manufacturers | DLW, Parel Workshop | |
| Engine | Alco 251-D, Inline-6, 1400hp (1300hp site rating) with Alco turbocharged engine. 1,100 rpm max, 400 rpm idle; 228x bore x stroke; compression ratio 12.5:1. | |
| Transmission | Electric, DC-DC (DC Generator and DC Traction motor) | |
| Traction motors | GE for original Alco and MLW models, BHEL for DLW | |
| Axle load | 21t | |
| total weight | 113t | |
| Bogies | Alco design cast frame trimount (Co-Co) bogies | |
| Starting TE | 34t, at adhesion 27% | |
| Length over buffer beams | 17370abbr=onNaNabbr=on | |
| Distance between bogies | 10516abbr=onNaNabbr=on |