WAG-12: Alstom’s New 12,000 hp Locomotive Enters Service on Indian Railways. See Specifications, New Features and More Inside

The much-awaited WAG-12 locomotive has been commissioned into revenue service by the Indian Railways. A long-haul train was worked by this locomotive in Mughalsarai division. The locomotive has been allocated a block of road numbers starting from 60000 onwards.

Based on the Prima Kz8A platform, the Alstom manufactured locomotive is primarily meant for service on the Eastern Dedicated Freight Corridor (EDFC). However, with the DFC not commissioned fully yet, the WAG-12 will operate on the IR network.

WAG-12 has two variants; The first model was the WAG-12A, of which only one unit has been manufactured. This design experienced issues with ride quality, which resulted in major modifications to the suspension and the bogies.

The final design, now known as WAG-12B, has been approved by the Indian Railways. This design is now heading for serial production at the new factory set up at Madhepura in Bihar.

Technical Specifications of the WAG-12B

WAG-12B variant with modified bogies and longer body

Axial ArrangementBo-Bo (For each of two units)
Number of Axles8
Mass of Locomotive180 Tons, Upgradeable to 200 Tons
Length19,200 mm per unit, 38,400 mm total length
Centre-To-Centre Distance Between Bogies10,200 mm
Maximum Speed100 km/h, Upgradeable to 120 km/h
Continuous Speed60 km/h
Max Load Haulage6,300 tons, 1:150 Gradient, 60 kph for 25 Ton Per Axle Variant
OHE VoltageNominal: 22.5 kV, 50 Hz
Maximum: 31 kV
Minimum: 17 kV
Traction Power (Continuous Rating)9,000 kW (12,069 hp approx)
Max Starting TE at 25t Axle Load / 22.5t Axle Load785 kN / 705 kN
Braking Effort563 kN
Max Braking Effort79.315 kN per motor
Stopping Distance900 metres: 100 kph to 0 kph
Remote Multiple Unit OperationsYes, 2 Locomotives
Traction MotorAsynchronous, Nose Suspended
Maximum RPM2,711

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New Features on the WAG-12

  1. Two units (A and B) permanently coupled to each other. Both units only have cabs on the outward-facing ends.
  2. Both units will be controlled from the working cab.
  3. While both units will be provided with one pantograph each. However, only one pantograph will be raised at a time and will feed power to both the units through a high-tension overhead link.
  4. Both units have been provided with a toilet for the crew.
  5. The units are connected to each other through a vestibule and gangway.
  6. A major departure from existing designs of locomotives is that high voltage apparatus like the vacuum circuit breaker is now inside the body of the locomotive in a special cubicle. The roof of the locomotive is almost empty except for the pantograph.
  7. This locomotive has a larger wheel diameter, compared to other freight locomotives in service on the IR.
  8. This locomotive also features the much-awaited ‘Brake Blending’ facility. If regenerative braking (AKA electric or Electro-Dynamic brake) is applied and found insufficient, a proportionate quantum of the pneumatic brake is applied simultaneously by the locomotive.
  9. To improve reliability, almost all hardware switches and controls are replicated on the DDU (Driver Display Unit). Thus, several functions can also be controlled using ‘Soft Keys’.
  10. A dehumidifier for air intake ensures that only dry air is used for cooling and ventilation systems. This will improve equipment life and insulation.
  11. An automatic flap system regulates the entry of air into the locomotive’s ventilation system and ensures uniform flow in various conditions.
  12. Tube drive equipped with self-aligning roller bearings for better suspension

Differences Between WAG-12A and WAG-12B

Limitations of the original WAG-12 design resulted in modifications and the WAG-12B variant. Here are the key differences between both types.

Total Length35,000 mm38,400 mm
Bogie DesignFlat solebarGooseneck or handlebar shaped solebar
Traction link coupling between the bogie and bodyBelow the driving cabTurned around and now provided in the middle of the body
Center to center distance between the bogiesLower (8,500 mm)Higher (10,200 mm)

How Indian Railways has Changed Direction with WAG-12

With WAG-12, the Indian Railways have switched to a new freight traction philosophy. The traditional Indian Railways model has been of hauling freights with either a single locomotive or combining two or more of them into multiple unit formations.

If the need for higher power arose, the usual approach was to work towards increasing the power of a single locomotive. Multiple-unit locos as were never a long term option under consideration. For the rest of the Indian Railways network, this philosophy still holds true. The recent outturn of the new 9,000 HP WAG-9 locomotive variant, classified WAG-9HH, is testimony to the policy.

With the WAG-12, IR has changed strategy. The WAG-12 is a permanently coupled set of two units. It has a larger number of axles and a higher combined power rating of 12,000 hp for the set. The higher number of axles will ensure improved adhesion and thus Tractive Effort (TE).

More WAG-12 Variants Coming?

The WAG-12 is likely to see a heavier 25-ton axle load variant in the next few years once he Dedicated Freight Corridors open up fully for operations. There may also be a higher speed 120 km/h version capable version available in future for loads like container trains.

With 800 units set to be delivered to IR over the next few years, the WAG-12 class is set to become a regular feature on Indian Railways’ heavy freight routes soon.

Update: See Alstom and Indian Railways Official Press Releases

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About the Author: Khalid Kagzi


  1. A report from a railfan’s perspective. Sharing it on my FB page. Thank you, Khalid/RailPost!

  2. Wow Khalid bhai, you sure do have a lot of information about the insides of railway!

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