Indian Railways Fan Page: Classification of Locos

In India, locomotives are classified according to their track gauge, motive power, the work they are suited for and their power or model number. The class name includes this information about the locomotive. The first letter denotes the track gauge. The second letter denotes their motive power (Diesel or Electric) and the third letter denotes the kind of traffic for which they are suited (goods, passenger, mixed or shunting). The fourth letter used to denote locomotives' chronological model number. A locomotive may sometimes have a fifth letter in its name which generally denotes a technical variant or subclass or sub type. fifth item is a letter that further refines the horsepower indication in 100 hp increments: 'A' for 100 hp, 'B' for 200 hp, 'C' for 300 hp, etc. So in this scheme, a WDP-3A refers to a 3100 hp loco, while a WDM-3F would be a 3600 hp loco.

The first letter (gauge)

W – Indian broad gauge ( 5 ft 6 in)
Y – metre gauge (3 ft or 100 0mm)
Z – narrow gauge(2 ft 6 in)
N – narrow gauge (2 ft)

The second letter (motive power)

D – diesel
C – DC electric
A – AC electric
CA – both DC and AC
B – Battery electric locomotive (rare)

The third letter (job type)

G – goods
P – passenger
M – mixed; both goods and passenger
S – shunting
U – electric multiple unit
R – Railcars

For example, in "WDM 3A":

"W" means broad gauge
"D" means diesel motive power
"M" means suitable for both goods and passenger service
"3A" means the locomotive's power is 3,100 hp ('3' stands for 3000 hp, 'A' denotes 100 hp more)

Diesel Locos Specification:
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WDM-1
Maker:          Alco
Wheels:        Co-Co
HP:    1950
Max Speed: 104
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WDM-2
Maker: Alco/ DLW
Wheels: Co-Co
HP: 2600
Max Speed: 120
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WDM-3A
Maker: DLW
Wheels: Co-Co
HP: 3100/3300
Max Speed: 120
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WDM-3D
Maker: DLW
Wheels: Co-Co
HP: 3300
Max Speed: 160
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WDM-4
Maker: GM
Wheels: Co-Co
HP: 2600
Max Speed: 130
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WDM-6
Maker: DLW
Wheels: Bo-Bo
HP: 1350
Max Speed: 75
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WDM-7
Maker: DLW
Wheels: Co-Co
HP: 2000
Max Speed: 100
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WDP-1
Maker: DLW
Wheels: Bo-Bo
HP: 2300
Max Speed: 140
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WDP-2 (WDP-3A)
Maker: DLW
Wheels: Co-Co
HP: 3100
Max Speed: 140
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WDP-4
Maker: GM/DLW
Wheels: BO1-1BO
HP: 4000
Max Speed: 160
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WDP-4B
Maker: DLW
Wheels: CO-CO
HP: 4500
Max Speed: 130
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WDG-3A
Maker: DLW
Wheels: CO-CO
HP: 3100
Max Speed: 100
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WDG-3D
Maker: DLW
Wheels: CO-CO
HP: 3400
Max Speed: 100
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WDG-4
Maker: GM/DLW
Wheels: CO-CO
HP: 4000
Max Speed: 120
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WDS-4
Maker: CLW
Wheels: C
HP: 600
Max Speed: 65
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WDS-4D
Maker: CLW
Wheels: C
HP: 700
Max Speed: 60
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YDM-1
Maker: North British
Wheels: B-B
HP: 700
Max Speed: 88
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YDM-4
Maker: ALCO/DLW
Wheels: Co-Co
HP: 1400
Max Speed: 96
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ZDM-3
Maker: CLW
Wheels: B-B
HP: 700
Max Speed: 50
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ZDM-4A
Maker: CLW
Wheels: 1-B-B-1
HP: 700
Max Speed: 50
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NDM-1
Maker: CLW
Wheels: B-B
HP: 2x145
Max Speed: 33
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Electric Locos Specification:
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WCP-1
Maker: SLM/MetroVick
Wheels: 2-BO-A1
HP: 2160
Max Speed: 120
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WCM-1
Maker: VF/EE
Wheels: Co-Co
HP: 3700
Max Speed: 105-120
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WCM-5
Maker: CLW
Wheels: Co-Co
HP: 3700
Max Speed: 120
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WCM-6
Maker: CLW
Wheels: Co-Co
HP: 5000
Max Speed: 105
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WCG-1
Maker: SLM/VF/MetroVick
Wheels: C+C
HP: 2600-2890
Max Speed: 80
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WCG-2
Maker: CLW
Wheels: Co-Co
HP: 4200
Max Speed: 80
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YAM-1
Maker: Mitsubishi
Wheels: B-B
HP: 1740
Max Speed: 80
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WAM-1
Maker: K-M/Krupp/Alst/Niv./SFAC
Wheels: B-B
HP: 3010
Max Speed: 112
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WAM-3
Maker: Mitsubishi
Wheels: Bo-Bo
HP: 2910
Max Speed: 112
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WAM-4
Maker: CLW
Wheels: Co-Co
HP: 3850
Max Speed: 120
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WAP-1
Maker: CLW
Wheels: Co-Co
HP: 3900
Max Speed: 130
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WAP-4
Maker: CLW
Wheels: Co-Co
HP: 5350
Max Speed: 140
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WAP-5
Maker: ABB/CLW
Wheels: Bo-Bo
HP: 6000
Max Speed: 160
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WAP-6
Maker: CLW
Wheels: Co-Co
HP: 5350
Max Speed: 160
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WAP-7
Maker: CLW
Wheels: Co-Co
HP: 6350
Max Speed: 140
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WAG-1
Maker: Niv./SFAC/CLW
Wheels: B-B
HP: 2930
Max Speed: 80
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WAG-5
Maker: CLW/BHEL
Wheels: Co-Co
HP: 4360
Max Speed: 100
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WAG-6B
Maker: Hitachi
Wheels: Bo-Bo-Bo
HP: 6110
Max Speed: 100
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WAG-7
Maker: CLW
Wheels: Co-Co
HP: 5350
Max Speed: 100
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WAG-9
Maker: ABB/CLW
Wheels: Co-Co
HP: 6125
Max Speed: 100
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WCAM-1
Maker: CLW
Wheels: Co-Co
HP: 3850 AC/2930 DC
Max Speed: 120 AC/100 DC
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WCAM-2
Maker: BHEL
Wheels: Co-Co
HP: 3780 DC/ 4720 AC
Max Speed: 105 DC/ 120 AC
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WCAM-3
Maker: BHEL
Wheels: Co-Co
HP: 4600 DC/ 5000 AC
Max Speed: 105
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