Indian locomotive class WDM-7

Indian locomotive class WDM-7
WDM-7 #11008 hauling a freight train; this loco is fuelled by bio-diesel
Type and origin Power type diesel Builder BLW Model DL560C Build date 1987-1989 Total produced 15
Specifications Configuration: ​  • UIC Co′Co′  • Commonwealth Co-Co Gauge 1,676 mm (5 ft 6 in) Bogies ALCO Asymmetric cast frame trimount Wheel diameter 1,092 mm (3 ft 7 in) Wheelbase 12.834 m (42 ft 1+1⁄4 in) Length 17.12 m (56 ft 2 in) Width 2.864 m (9 ft 4+3⁄4 in) Height 4.185 m (13 ft 8+3⁄4 in) Axle load 17,800 kg (39,200 lb) Loco weight 96,000 kg (212,000 lb) Fuel type diesel Fuel capacity 5,000 L (1,100 imp gal; 1,300 US gal) Prime mover ALCO 251-B RPM range 400–1000 rpm Engine type V12 diesel Traction motors BHEL 4906 BZ and 4907 AZ Cylinders 12 Cylinder size 228 mm × 266 mm (8.98 in × 10.47 in) bore×stroke Transmission Diesel-electric transmission MU working 2 units Train brakes Air, Vacuum and Dual
Performance figures Maximum speed 105 km/h (65 mph) Power output Max:2,000 hp (1,500 kW) Site rated:1,800 hp (1,300 kW) Tractive effort 25.3 t (25 long tons; 28 short tons)
Career Operators Indian Railways Numbers 11001-11015 Locale SR Disposition active

The WDM-7 is a diesel-electric locomotive of Indian Railways. It has been manufactured by Banaras Locomotive Works (BLW), Varanasi. The model name stands for broad gauge (W), diesel (D), mixed traffic (M) engine. Today, these are found exclusively at Chennai Central and nearby area.

These units have been retro-fitted with air brakes, in addition to the original vacuum brakes. The WDM-7 locos have a maximum speed of 105 km/h (65 mph), restricted to 100 km/h (62 mph) when run long hood forward - the gear ratio is 94:17.

TNP WDM-7 resting in siding

History

Fifteen of these locomotives (road numbers #11001 to #11015) were built from 1987 to 1989 as a low-powered, “lightweight” version of the original ALCO. Like the WDM-6, maybe IR wanted a lower powered locomotive to handle small rake local and passenger services. However, all sheds declined them and they ended up at Ernakulam where they were used to handle local and shuttle services with good degrees of efficiency. Becoming aware of their abilities, SR moved all the WDM-7s out of Ernakulam to Tondiarpet, where they are housed today. These days, they are seen being used as shunters at Chennai Central or for light passenger haulage. One (#11008) has been modified to run on bio-diesel.

These Co-Co diesel-electric locomotives were designed primarily for branch-line duties (top speed 105 km/h). They have two 3-axle bogies. The power-pack is a 12-cylinder Alco 251B unit. They are a lower-powered variant of the WDM-2 (the latter produces 2600 hp of usable power, as opposed to the WDM-7 which produces 2000 hp). They were formerly housed at Erode and Golden Rock as well. They are reliable and rugged locomotives even though low-powered. They can be easily recognised by the lack of grilles on the short hood; in fact, they look exactly the same as the WDM-2 except for the “clean” short-hood-forward nose without grilles. Two locos currently operate on a mixture of bio-diesel and diesel. As of today, all 15 built are still in service.

Locomotive shed

Zone	Name	Shed Code	Quantity
Southern Railway	Tondiarpet	TNP	15
Total Locomotives Active as of October 2021			15

Former

• Ernakulam
• Erode
• Golden Rock

See also

• Indian locomotive class WDM-2
• List of diesel locomotives of India
• Rail transport in India
• Rail transport in India#History

References

Bibliography

• Hughes, Hugh (1996). Indian Locomotives: Part 4 – 1941–1990. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9521655-1-1. OCLC 35135033.

External links

• Ministry of Railways (Railway Board)
• [IRFCA] Indian Railways Locomotive Roster Changes