The model name stands for broad gauge (W), Diesel (D), Mixed traffic (M) engine, 2nd generation (2).

The WDM-2 is one of the most successful locomotives of Indian Railways[peacock prose] serving both passenger and freight trains for over 60 years.

Despite the introduction of more modern types of locomotives like WDG-4 and electrification, a significant number are still in use, both in mainline and departmental duties.

[1] Therefore, required building a large number of Co-Co diesel locomotives producing at least 2,600 hp (1,900 kW) with road switcher cabs to achieve this aim.

Initially, the Indian railways invited tenders to build locomotives to the new specification.

Since General Motors did not agree to the transfer of technology agreement, the ALCO prototype was selected for production.

[5] However WDM-1s were not selected for mass production because of having only one forward cab at one end which needed a lot of turntables.

[13] Although ALCO went bankrupt, DLW Varanasi successfully adapted the technology and produced many upgraded versions which were exported to many Broad Gauge countries.

A few WDM-2 locomotives had been rebuilt by Diesel Loco Modernisation Works (DLMW) in Patiala, Punjab.

[16] The whole batch of WDM-2 imports went all to the Diesel locomotive shed at Katni (KTE).

[25] However the WDM-2 was very easy to operate and maintain because of its simple construction and mechanics which resulted in it being very reliable.

It is the dedicated freighter version of the WDM-2 and shares the same engine and horsepower rating with WDM-3A.The first units of this class was delivered on 18 July 1995 under the model name of WDG-2.

All the older locomotives built by DLW had a regular WDM-2 type square short hood profile and control stand position.

These can be found all over India performing various duties like hauling freight and passenger service to shunting and departmental works.

It is a dedicated passenger version of the WDM-2/3A, similar to how the freighter WDG-2/3A was developed, but unlike its mixed-use and freight-dedicated counterparts, this locomotive features an aerodynamic streamlined dual-cab design, similar to its AC-electric counterparts, like the WAP-1 and WAP-4, making it the first dual-cab diesel–electric locomotive of India, preceding the EMD 710 based WDP-4D, and the Only dual-cab member of the ALCO DL560C family.

The WDM-2 locomotives from serial numbers around 17788 to 17890 were fitted with full-width short hoods with the intention of improving visibility for drivers.

These locomotives are easily recognisable by their short hoods with large windows.

After over-ageing of these locomotives, the jumbos were mainly used on shunting or departmental works trains.

[32] These are relegated to shunting duties, and occasionally haul Departmental works trains.

Unlike their Indian counterparts, these locomotives do not have the dynamic braking system.

Locomotive number 18040 is the first in the series to be imported; subsequent ones were later supplied by ALCO.

These WDM-2 locomotives can be easily identified by their original ALCO dynamic brake vents with three partitions.

After 18232, DLW started manufacturing locomotives from kits supplied by ALCO.

Some of these locomotives (like WDM-2 18236) have retained their original ALCO dynamic brake vents with three partitions.

These locomotives were mostly in mainline service till 2007, thereafter relegated to shunting/departmental duties like ALCO-built ones.

The 17 series locomotives are no longer used for mainline services; these are now fit only for shunting and inferior activities with most of them being condemned or scrapped.

They are originally WDM-2s and all were rebuilt to WDM-3A standards (except for locomotives lost to collision damage).