Which locomotive is better WDG4 or WDP4

IR class WDG-4

The WDG-4, Manufacturer designation EMD GT46MAC and EMD GT46ACe for the upgraded version is an Indian Railways diesel locomotive with three-phase electrical power transmission. General Motors Electro-Motive Division (GM EMD) manufactured the series in 1997 in two lots, from 2002 it was also built under license by the Diesel Locomotive Works (DLW) in India. The series designation consists of W. For wide'Breitspur', D for diesel, G For goods 'Goods' for a freight locomotive and the 4 behind the hyphen, which stands for a locomotive with an output between 4000 and 5000 hp.[1]

WDG-4 No. 12029 in the paint of the Krishnarajapuram depot (KJM) in the greater Bengaluru area
Numbering: 12001–12999
Number: 1188
Manufacturer: GM EMD, DLW
Large components from BHEL and Siemens
Year of construction (s): GM EMD: 1997-1998
DLW: 2002–2017
Axis formula: Co’Co ’
Gauge: 1676 mm
Length over coupling: 21,240 mm
Height: 4160 mm
Width: 3070 mm
Service mass: 126 t
Wheelset traveling mass: 21 t
Top speed: 120 km / h
Installed capacity: 4000 hp
Starting tractive effort: 540 kN
Braking force: 270 kN
Wheel diameter: 1092 mm
Motor type: EMD 16-710G3B
Motor type: Two-stroke V16 with exhaust gas turbocharger
Rated speed: 950 min−1 (8th gear)
Power transmission: electrical, three-phase generator with three-phase asynchronous motors
Tank capacity: 6000 l
Number of traction motors: 6 pieces Siemens 1TB2622-0TB02
Drive: Pawbearing drive
Transmission ratio: 1:5,29
Locomotive brake: Drag brake,
Direct brake
Train brake: Compressed air brake, brake computer from Knorr-NYAB



The structure of the WDG-4 corresponds to the standard diesel locomotives built by GE EMD for the North American market. They are equipped with a 16-cylinder two-stroke diesel engine of the EMD series 710, which could deliver an output of 4,000 hp in the older locomotives.

From summer 2007, the WDG-4 was manufactured in an upgraded version, whereby the power of the diesel engine was increased to 4500 HP and the converters were converted from GTO thyristor technology to IGBT technology. The execution is provided by GE EMD as EMD GT46ACe designated, but received no new series designation from Indian Railways. The new version was produced from around locomotive No. 12114.[3]


The locomotive is built on a rigid frame. It is supported by four rubber springs on the two three-axle bogies, the frames of which are cast from high-strength steel. GM EMD used the term HTSCwhich, according to the manufacturer, the meaning high traction / speed three axleHas 'high traction / speed - three axes'. As in the axis sequence designation, the number of axles is indicated with the letter C. expressed.[4] Indian Railways documents the meaning of HTSC mostly with High tensile steel cast“High-strength cast steel” is indicated.[5] The longitudinal forces are transmitted from the bogie to the locomotive body via a sleeve which is connected to the bogie frame with two control arms so that it can move laterally and encompasses a king pin on the locomotive body.[6]


The diesel engine transfers its power to the main generator, which is flanged directly to the crankshaft. The EMD TA 17 generator consists of the armature with the excitation winding, which generates three-phase alternating current in the two separate stator winding systems. Each winding system supplies the energy to a rectifier bridge attached to the generator. The two bridges are connected in series. Depending on the speed and excitation, the generator delivers between 600 and 2600 V direct current.[7] The direct current is converted by converters into three-phase alternating current of variable frequency and fed to the three-phase asynchronous traction motors, which drive the axles as a pivot bearing drive. The converters were developed by Siemens, the power semiconductors are cooled by heat pipes. A Sibas 16 microprocessor control from Siemens controls the drive train, and a radar system aimed at the ground is used for slip control.[2]

Many locomotives are with that Auto-emergency brakes (AEB) - a system that automatically triggers an emergency brake when driving downhill if the train exceeds a preprogrammed speed. The system is activated by a key and is used, for example, on the steep section of the Braganza Ghats on the border between the states of Goa and Karnataka.[8]

Individual evidence

  1. Classification of Locos. IRFCA, accessed on August 5, 2020.
  2. abWDG-4. In: Indian Railways FAQ: Locomotives. IRFCA, accessed on August 18, 2020.
  3. Loco Roster Database. IRFCA, accessed on August 18, 2020.
  4. ↑ Service Department Electro-Motive Division General Motors Corporation (Ed.): Maintenance Instruction M.I. 1517 revision A. November 2002, 8.
  5. ↑ Indian Railways Center for Advances Maintenance Technology (Ed.): Handbook on WDP4 / WDG4 Locomotives for Maintenance Staff. Maharajpur October 2013, 19 Undertruck, p.76.
  6. ↑ Service Department Electro-Motive Division General Motors Corporation (Ed.): Maintenance Instruction M.I. 1517 revision A. November 2002, p.9.
  7. ↑ Indian Railways Center for Advances Maintenance Technology (Ed.): Handbook on WDP4 / WDG4 Locomotives for Maintenance Staff. Maharajpur October 2013, 9.1 Traction Alternator, p.26.
  8. Auto-Emergency Brakes (AEB). In: IRFCA. Retrieved August 18, 2020.
Steam locomotives
Diesel locomotives
Universal locomotives

WDM-1 • WDM-2 (2A, 2B) • WDM-2G • WDM-3 • WDM-3A (3C) • WDM-3D (3B, 3E, 3F) • WDM-4 • WDM-6 • WDM-7

Passenger locomotives

WDP-1 • WDP-2 / 3A • WDP-4 (4B, 4D)

Freight locomotives

WDG-2 / 3A (3B, 3C, 3D) • WDG-4 • WDG-4G • WDG-5 • WDG-6G

Shunting locomotives

WDS-1 • WDS-2 • WDS-3 / 4C • (WDS-4A, 4B, 4C, 4D) • WDS-5 • WDS-6 • WDS-8

DC electric locomotives
AC electric locomotive
Multi-system locomotives
Two-engine locomotives