Indian locomotive class WDM-2

The first few prototype WDM-2 were imported with locomotive number 18040 being the first WDM-2 of India.[7][8] The need for a large number of locomotives quickly was deemed paramount. After Banaras Locomotive Works (DLW) completed construction of its factory in Varanasi, production of the locomotives began in India.The first 12 locomotives were built using kits imported from ALCO (order no. D3389) in the United States.[9]

The first diesel loco assembled in DLW was locomotive number 18233 and the first fully-built WDM-2 from DLW was 18299.[10][11][12] After that DLW started manufacturing the WDM-2 locomotives from their own components. Since then over 2,800 locomotives have been manufactured with 16887 being the last locomotive in the series.[13]

Although ALCO went bankrupt, DLW Varanasi successfully adapted the technology and produced many upgraded versions which were exported to many Broad Gauge countries.[14] Later a number of modifications were made and a few sub-classes were created. This includes WDM-2A, WDM-2B and WDM-3A (formerly WDM-2C). A few WDM-2 locomotives had been rebuilt by Diesel Loco Modernization Works (DLMW) in Patiala, Punjab.[15] These are fitted with Daulat Ram DBRs.[16]

The whole batch of WDM2 imports went all to the Diesel locomotive shed at Katni (KTE).[17] Locomotive number 18040 was first loco in the series, but 18042 was the first WDM-2 unit to be commissioned. By 1967 the first express trains were being hauled by the WDM-2 instead of steam locomotives. Trains like the Himgiri express and Tamil Nadu express were entirely hauled by WDM-2 units.[18][19] One of the most important express trains hauled by the WDM-2 class was the Mumbai Rajdhani express.[20][21] By the 1980s the WDM-2 class was hauling most of the passenger and freight trains in India.

The WDM-2 locomotives have a maximum speed of 120 km/h (75 mph), restricted to 100 km/h (62 mph) when run long hood forward.[22]

The WDM-2 has a maintenance schedule of 3000 km or 10-days, which was recommended by ALCO.[23] These have been extended by 20 days to 30 days by using better and more efficient lubrication oils and other component fluids and improving some bearings for the suspension. The original WDM-2 bearings were very failure prone and often required minor repairing.[24] 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. This maintenance is usually done at the nearest Diesel loco shed.

The WDM-3A class is actually upgraded WDM-2 designed to produce more power (3100 hp instead of 2600 hp) and increased reliability (roller bearings instead of conventional ALCO bearings). Except 150 units, rest are rebuilt WDM-2. Rebuilt WDM3As can be identified by an “R” at the end of their road number.

The WDG-2/3A is the freight variant of WDM-2

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 July 18, 1995 under the name of WDG-2. The class was manufactured till end of 2015. All the older locomotives built by DLW had regular WDM-2 type, square short hood profile and control stand position. The Bogies of WDM-2 have been replaced by High adhesion Fabricated bogies for better traction and Stability.

They are hugely successful with about 1163 units of this class have been produced. They can be found all over India doing all kinds of duties like hauling freight and passenger service to shunting and departmental works.

They are lower powered (2000 HP instead of 2600 HP) version of the WDM-2. These locomotives were built from 1987 to 1989. A few were at Ernakulam earlier, but later all were transferred to Tondiarpet seen shunting at Chennai Central or for light passenger haulage. Some are at the thermal power station, Chennai.

They were formerly housed at Erode and Golden Rock also. They are reliable and rugged locomotives even though low powered. They can be easily recognized by the lack of grilles on the short hood. Two locomotives are running on a mixture of bio-diesel and diesel. All 15 are still in service.

It is a lower powered passenger (2300 HP) version of the WDM-2. The Bogies of WDM-2 have been replaced by Bo-Bo fabricated bogies with a max. Speed of 140 km/h. They were not hugely successful. About 69 units have been produced with 60 locomotives still being in service. They are easily identified by baldie grille-less short hood.

The WDM-2A is a variant of the original WDM-2 series that have been retro-fitted with air brakes, in addition to the original vacuum brakes.[25] So these locomotives can haul both vacuum and air braked wagons. Air brakes were introduced as the were safer and more reliable.[26] Despite this classification some WDM-2A locomotives are still marked as WDM-2 not as WDM-2A

The WDM-2B is a variant of the original WDM-2 series built with air brakes as original equipment. They do not have vacuum brakes.[27] Only some have been classified as WDM-2B.

Jumbo variant of the WDM-2

The WDM-2 locomotives from serial numbers around 17788 to 17890 were fitted with full-width short hood with the intention of giving them an extended visibility for the drivers.[28] These are unofficially termed 'Jumbos' by crew and Rail-fans.[29] WDM-2 #17722 and 17748 are rumored to be the prototypes of the jumbo class, but differs slightly from other Jumbos.[30][31][32] But these locomotives proved to be not that useful as the locomotive pilots raised their concerns that they had to stand up to operate them. So a few were modified to have normal short hoods of WDM-2.Some earlier Jumbo locomotives were also converted to WDM-3A.

These locomotives are easily recognizable by their short hood having big windows. After over-ageing of these locomotives, the jumbos were mainly used on Shunting or Departmental works trains. As a consequence few of them are still in service.

This classification is given to WDM-2 which are nearing the end of their service life. These locomotives can be easily recognized by '0' at the beginning of their road number.[33] These WDM-2 locomotives are relegated to do Shunting or occasionally haul Departmental works trains.[34] Some WDM-2 remain in classification for many years before they are scrapped.

WDM-2, operated as the Class M8 in Sri Lanka

Eight WDM-2 locomotives were purchased by the Sri Lanka Railways, the state run railroad operator in Sri Lanka in 1996. They were the longest and most powerful locomotives at that time. They were allocated the M8 class.[35][36] However, some modifications to the appearance were done by SLR.[37] These locomotives belong to road number 841 to 848 and all are still operational.

Ten WDM-2 locomotives were purchased by Bangladesh Railway in 2001. They were the most powerful locomotives at that time. They were allocated Class 6400 or BED-26 numbered from 6401 to 6410. All are fitted with air brake and AAR coupling. Unlike their Indian counterparts, these locomotives do not have the dynamic braking system. All locomotives are still in service

These locomotive were among the first WDM-2s to roam India. Locomotive number 18040 is the first in the series to be imported and subsequent ones were later supplied by ALCO. Locomotives numbered from 18080 to 18111 are actually WDM-4 class. These WDM-2 locomotives can be easily identified by their original ALCO dynamic brake vents with three partitions.[39] They were mostly in mainline service till 2007 and were relegated to shunting/departmental duties thereafter. The last of these locomotives (WDM-2 numbered 18068 from kurla) were condemned by March 2014.[40][41] All of these locomotive has been withdrawn from service and scrapped now.

After 18232, DLW started manufacturing locomotives from kits supplied by ALCO. The first kit-built from DLW was 18233 name 'kundan' and subsequent ones were later assembled in DLW from kits supplied by ALCO after technology transfer took place. Some of these locomotives (like WDM-2 18236) have retained their original ALCO dynamic brake vents with three partitions.[42] The first fully-built WDM-2 from DLW was 18299.These locomotives were mostly in mainline service till 2007 and were relegated to shunting/departmental duties thereafter like ALCO built ones. The last of these locomotives (WDM-2 numbered 18473) were condemned by November 2013.[43]

After 18514, DLW started manufacturing locomotives with 17 series

DLW stopped 18 series midway (18499) and started producing 17 series locomotives. Locomotives numbered from 17000 to 17099 are WDM-1 class. These were fully-built WDM-2 locomotives from DLW. The loco numbers 17796-17895 are the 'Jumbo' versions of WDM-2. Almost all of the jumbos WDM-2 belongs to this series. Most of these locomotives were manufactured in the 70's. The 17 series locomotives are no more used for Mainline services, these are now fit only for shunting and inferior activities with most of them being condemned/scrapped.[44]

18514-18522 are WDM-3 locomotives built by German Manufacturers Henschel.

The locomotives numbering from 18530+ onward were manufactured from early 1980's. Almost all locomotives were rebuilt to WDM-3A standards, but most reverted to WDM-2 standards as they reach the end of their service life. A few are still in mainline service as WDM-3As. Most of them are fit only for shunting and inferior activities with half of them being condemned/scrapped. They still have about 1–2 years of railway service left in them.

18901 and 18902 are WDM-6 which are no longer in service

The 16 series are the youngest in the WDM-2 series. The oldest of their series locomotive number 16001 was manufactured in mid 80's. They are originally WDM2's and all were rebuilt to WDM-3A standards except for locomotives lost to accident damage.[45] All 16 series locomotives are still running in mainline duties as WDM-3A class. About 30 units remain as pure WDM-2s are still in service. Scrapping of the 16 series has now begun.