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  • Top: WDP-4 20005 in Short hood Forward mode
  • Below: WDP-4 20044 in Long hood Forward mode.
Type and origin
Power typeDiesel-electric
BuilderEMD & DLW
Build date(EMD) 2001
(DLW) 2003-2010
Total produced(EMD) 10
(DLW) 272 under license (in production)
 • AARB1-1B (WDP-4), C-C (WDP-4B/4D)
Gauge5 ft 6 in (1,676 mm)
  • Bo1-1Bo (WDP-4)
  • Co-Co (WDP-4B and WDP-4D)
Fuel typeDiesel fuel
Fuel capacity1,600 US gal (1,300 imp gal; 6,100 L)
Prime mover16-710G3B
Engine type2-stroke V16 diesel
Displacement11,360 cu in (186.2 L)
AlternatorTA-17-CA6A AC,
1 inverter per truck
Loco brakeAir
Train brakesAir
Performance figures
Maximum speed130 km/h (81 mph) (operational)
180 km/h (110 mph) (tests)
Power output
  • 4,000 hp (2,980 kW) (WDP-4)
  • 4,500 hp (3,360 kW) (WDP-4B and WDP-4D)
OperatorsIndian Railways

The EMD GT46PAC or WDP-4 is a passenger-hauling diesel-electric locomotive with AC electric transmission designed by General Motors Electro-Motive Division and built by both GM-EMD and under license by Diesel Locomotive Works (DLW) of Varanasi, India for Indian Railways as their classes WDP-4, WDP-4B and WDP-4D.[2] The GT46PAC is a passenger version of the previous Indian Railways EMD GT46MAC freight locomotive. The locomotive has a 16-cylinder 710G3B diesel engine with a maximum speed of 904 RPM.[3]


There are three variants of this loco - the original WDP-4 which is a 4,000 hp (2,980 kW) loco, the WDP-4B which is a 4,500 hp (3,360 kW)126 t (124 long tons; 139 short tons) weighted loco with a single cab and the newest WDP-4D which is a 4,500 hp (3,360 kW) loco with dual cabs.[4]


The locomotives are numbered from Road No. 20000 upwards till 20103 and further numbering of the loco along with its WDP-4B/4D variants has started from the 40XXX series. This is due to the numbering of the 20XXX series almost breaching the start of numbering of another locomotive class, the WCG-2 which is a DC electric locomotive whose numbering started from 20105.[5]


The WDP-4 is capable of hauling 24 coach trains at 110–130 km/h (68–81 mph). It has been also used for Spanish Talgo trial run at speed of 180km/h.

The locomotives can be used in either direction, and frequently haul trains long hood forward, as in the picture. Newer editions with 4500 hp have been produced which have been named with the sub class WDP-4B /WDP-4D which have different traction control with six traction motors and are Co-Co bogie equipped (more similar to WDG-4), unlike the original which has a Bo-1-1-Bo arrangement with four traction motors. Due to some visibility hindrances faced by loco pilots in driving long hood front, the basic WDP-4B model has been modified to dual cab to eliminate any such possibility. The other features of the WDP-4B and the WDP-4D are the same. The newer cabs have slightly wider profiles to improve visibility.

Some of the WDP-4B/WDP-4D locomotives have been spotted having a provision for an inverter-driven head-end power unit which allows trains to be run without an End-on generating car (EOG) for hotel power.[6]

The loco is very fuel efficient and has minimal exhaust emissions unlike ALCO based locomotives, thanks to its 2 stroke high efficiency diesel engine[citation needed].


The first set of 10 locos starting from road number 20000–20009 were manufactured by the Electro Motive Division (EMD) of (General Motors) while road numbers 20011 upwards have been manufactured by Diesel Locomotive Works (DLW) of Varanasi in collaboration with EMD and GM (General motors). Siemens too are part of this group providing a large component of the electronics on board this loco.[7]


The WDP-4B class variant of GT46PAC

The locomotive is used on the following zones of Indian Railways:


This locomotive is currently housed at eight sheds in the Indian Railways, spread across the country which are Hubli (Code:UBL) and Krishnarajapuram (Code:KJM) in the South Western Railway zone, Golden Rock(code:GOC) in the Southern Railway Zone, Siliguri (Code:SGUJ) in the Northeast Frontier Railway zone, Bhagat Ki Kothi (Code:BGKT) in the North Western Railway zone, Itarsi (Code:ET) in the West Central Railway, Tughlakabad (Code:TKD) of the Northern Railway, Gooty (Code:GY) in the South Coast Railway, Pune (code:PUNE), Kalyan (code:KYN) in Central Railways and Izzatnagar (code:IZN) in the North Eastern Railway, Vishakhapatnam (code:VSKP) in South Coast Railways [8]

A WDP4D of Gooty Loco Shed hauling Pune Secunderabad Shatabdi Express near Lingampally
A WDP4D of Kalyan loco shed hauling Konark Express near Secunderabad


The Hubli shed is the parent shed of all the EMD sheds in India. The shed homes the largest number of EMD locomotives in India[9] and currently homes these locos with following road numbers:

  • WDP-4: 20005–20009, 20020–20022,20024–20027,20031–20033, 20035 and 20065.
  • WDP-4B: 40007–40010,40015,40016,40018,40036,40046 and 40054–40057
  • WDP-4D: 40517–40519, 40521, 40522, 40543–40547


The Krishnarajapuram diesel locomotive shed currently homes these locos with the following road numbers:

  • WDP-4: 20019, 20023, 20028–20030, 20034, 20036–20046, 20053–20060, 20062, 20067 and 20068
  • WDP-4B: 40017, 40065 and 40066.
  • WDP-4D: 40226, 40228, 40236–40240, 40246, 40247, 40278, 40279, 40298, 40305, 40306, 40329, 40330, 40362, 40385, 40387, 40388, 40395, 40397, 40398, 40400, 40401, 40415, 40433–40435, 40450–40455, 40501, 40523, 40527–40531, 40534–40537, 40542, 40551–40555

It is also currently homing the 2000th HHP High Horse Power locomotive ever, manufactured by Diesel Locomotive Works, Varanasi. The loco is numbered #40387 and is named "Pratap".

Golden Rock[edit]

Golden Rock homes the following:

  • WDP-4B: 40063,40064,40067,40068,40075,40077
  • WDP-4D: 40093,40099,40100-40103,40105,40106,40114,40115,40133,40441


Erode Diesel Loco Shed homes the following WDP-4Ds. This is one of the sheds to home only WDP-4Ds WDP-4D: 40171, 40174, 40175, 40180, 40197, 40198, 40199, 40241, 40242, 40243, 40338,40339, 40488.


Siliguri houses the following locomotives:

  • WDP-4: 20000–20004, 20011–20018, 20048–20052, 20061, 20063–20064, 20066, 20069-20073, 20074, 20076, 20079, 20081–20085, 20094
  • WDP-4B: 20047, 20075, 40022–40025, 40028, 40029, 40032, 40035, 40037, 40045
  • WDP-4D: 40089–40091,40096,40108,40120,40129,40138, 40141.

Bhagat Ki Kothi[edit]

Bhagat Ki Kothi homes

  • WDP-4: 20085–20099, 20080, 20077, 20078 which are nicknamed 'Aravali' (named after the mountain ranges).
  • WDP-4B: 40027, 40030, 40031, 40033, 40034, 40038–40040, 40043, 40044, 40060
  • WDP-4D: 40086,40088,40092,40094,40095,40116,40127,40128


Tughlakabad (Code: TKD) homes

  • WDP-4B: 40001, 40003–40006, 40011–40013, 40019–40021, 40049–40051, 40058, 40059,40079
  • WDP-4D-40014,40026,40086,40087,40109,40110, 40122,40124,40125,40139


Itarsi (Code: ET) shed homes:

  • WDP-4B: 40041, 40042, 40047, 40048 and 40052, 40053, 40061 and 40062.


Gooty (Code:GY) shed homes:

  • WDP-4D: 40104,40111,40112,40113,40117,40118,40119,40121,40130,40135,40142,40148,40150,40152,40185,40186,40188,40192,


New Guwahati City[edit]

New Guwahati (code:NGC) shed homes:

  • WDP-4D:

40601,40602,40603,40604,40605, 40606,40607,40608


Pune (code:PUNE) shed homes:

  • WDP-4D:40143,40144,40153,40416,40417


Kalyan (code:KYN) shed homes:

  • WDP-4D: 40233,40234,40235"Gaurav",40260,40261,40276,40277,40312,40313,40316,40346,40347,40361,40372


There are many more sheds that home these locos and are going to home hese.Gonda(NE),Izzatnagar(NE),Samastipur(EC),Kalyan(CR),Vatva(WR),RTM(WR),Erode(SR). HOWRAH, JMP (ER), Bondamunda (SE), Raipur (SECR) are the few sheds which have received this class recently and home a smaller number as of now.One by one,most or all sheds are receiving EMD locomotives of both classes,WDP-4D and WDG-4D.


The use of the locomotives "long hood forward" has been criticised because the driver might have difficulty in seeing signals. This criticism has been rejected by Indian Railways.[10] But the solution to this problem is to upgrade all WDP-4 and WDP-4B models from single cabins to WDP-4D models of dual cabins.

Older locomotives of Indian Railways like the WDM 2 models have been upgraded from WDM 2 series to WDM 3 and WDM 3A series, to enhance other shortcomings in design of WDM-2 series.

See also[edit]


  1. ^ http://www.emdiesels.com/emdweb/international/gt46pac.jsp
  2. ^ http://www.dlw.indianrailways.gov.in/view_section.jsp?lang=0&id=0,295,329,389,391
  3. ^ "Details from production Factory".
  4. ^ "IRFCA".
  5. ^ "IRFCA".
  6. ^ "IRFCA".
  7. ^ "DLW site".
  8. ^ "IRFCA".
  9. ^ http://www.swr.indianrailways.gov.in/view_section.jsp?lang=0&id=0,1,808,813,814
  10. ^ Railway claims engine design not faulty - India News - IBNLive

External links[edit]