ALCO DL560C

The first loco of the type DL560C to arrive in India is WDM-2. Initial batches arrived from the ALCO manufacturing facility in ready-to-ride condition. And 12 more arrived from ALCO in, to be assembled kits. This loco remained as the workhorse of Indian Railways in the 20th century. This loco solely can haul 9 passenger and can haul 18 with the help of another WDM-2. This model had a maintenance schedule of 3000 km/10days. Later on, improving the fluid level and bearings, the schedule was increased to 30 days. The gear ratio being 65:18 and having a max speed of 120 km/h. JUMBOS (full-width short hood) and WDM-2A/2B are some of WDM-2s variants with minor modifications. The production began in the late 1960s, and went on till the late 1990s. They are being eventually retired. They belong to series 18xxx, 17xxx and 16xxx.[2]

WDM-3A, previously known as WDM-2C, are more powerful than the previous WDM-2 version by 500 hp. The first loco was delivered in 1994. This loco was capable of doing the work of two WDM-2S. They too had a top speed of 120 km/h. The gear ratio is same as that of WDM-2. There are some locomotives whose maximum hp has been tuned close to 3900 hp and named as WDM-3A. They are still under production. WDM-3C is an upgraded loco from its previous WDM-3A. Their series is 14xxx.[2]

This is the latest and the most advanced variant of all the available ALCOs. The WDM-3D are fitted with micro-processors. This variant has enhanced cabin facilities including left hand driving. This loco also has some features borrowed from its mate EMD GT46PAC. Features such as microprocessors to detect wheel slipping and phased manner power supply, monitoring engine parameters are incorporated from the latest EMD GT46PAC. This proved this variant a real success. Serial production began in 2005 and almost all diesel broad gauge sheds were allotted with this loco. The minor variants of this loco include WDM–3E and WDM–3F. They belong to series 11xxx.[2]

A WDG-3A of Kazipet Junction at Lingampally railway station

13109 'Shakti' WDG-3A Bondamunda at Kamakhya in July 2018 attached with another WDG-3A

WDG-3A, previously known as WDG-2 were designed owing to the problems which arose with WDM-2 on hauling freight. This loco normally hauls freight. The common problems were poor ride quality, lateral oscillations, and poor traction with heavy loads. First loco was manufactured in 1995. The gear ratio is 74:18. This loco has a balancing speed of 69 km/h with a load of 58 BOXN wagons (Max. speed 100 km/h). This variant is being gradually modernized to the level of WDM-3Ds. Some of its minor improvements include WDG-3B, WDG-3C and WDG-3D. Their series are in 14501-14999 and 13000-13665. Last one built for Indian Railway was 13665 rolled out in 2012. Total 1171 were built for Indian Railways and a considerable number were supplied to non Railway customers like thermal power plants, port trusts and steel plants. [2]

Main article: Indian locomotive class WDM-7

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.

WDM-2 - Class M8 In Sri Lanka

Main article: Sri Lanka Railways M8

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. However, some modifications to the appearance were done by SLR. These locomotives belong to road number 841 to 848 and all are still operational.

Main article: Bangladesh Railway Class 6400

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.

On 27 July, 2020 Indian Railways (IR) handed over 10 WDM-3D diesel locomotives to Bangladesh Railways under its “grant assistance” plan. The vehicles cost an estimated ₹600m ($US 8m) to manufacture. [3]