WDM-3

The Indian locomotive class WDM-3 is a class of Diesel–hydraulic locomotive that was developed in 1962 by Henschel for Indian Railways. The model name stands for broad gauge (W), Diesel (D), Mixed traffic (M) engine, 3rd generation (3). They were inducted into service between 1970 and 1971. A total of eight WDM-3s were built between 1962 and 1970. They were decommissioned at Gooty in 1995.

These diesel–hydraulic locomotives are not related to the ALCO WDM-3A. All are now retired from service.

History

Introduction

A Mechanical Engineer of the Indian Railways developed a new hydro-mechanical transmission for diesel locomotives. The design was examined by the National Research and Development Corporation and was patented in India (as Suri transmission) sometime in 1956–57. In 1962, the Railway Board thought of developing Suri transmission in high horse-power locomotives in order to utilise its maximum benefit. For this purpose, the Railway board, in April 1962, authorized to conduct negotiations with West German firms for 5,000 hp locomotives and with ALCO for 2,600 hp locomotives already under manufacture at Diesel Locomotive Works, Varanasi.

Selection of locomotives

Between 1962 and 1964, the Railway Board considered the question of procurement and development of Suri transmission in 5,000 hp locomotives, or alternatively 2,500 or 2,600 hp locomotives. Having regard to the then technical assessment that the maximum benefits of Suri transmission were likely to show in the higher horse-power range due to a better power/weight ratio, the Board considered it desirable to procure a few 5,000 hp locomotives with Suri/Mekydro transmission provided the prices were found to be reasonable and adequate guarantees on the performance of these locomotives engines and transmission systems were forthcoming.

In September 1964, the Railway Board issued tender inquiries to three West German firms. In response, offers were received from two firms that offered locomotives of 5,000 hp with two 2,500 hp Maybach engines. In June 1965, the Railway Board appointed a Technical Committee to examine these offers. The Committee was specifically asked to determine:

* Technical suitability of the 5,000 hp locomotives for the development of Suri transmission.
* In view of the difficulties experienced by American Railroads with 16 cylinders high-speed Maybach engines, what precautions should be taken to ensure that 20 cylinders high-speed Maybach engines (which were proposed to be fitted in the 5,000 hp locomotives) gave minimum trouble under Indian conditions of working.

The Technical Committee on various considerations came to the conclusion in December 1965 that no economic benefits of capital and maintenance costs could be expected of 5,000 hp locomotives as compared to those of dual coupled 2600 WDM-2. The Committee also stated that 5,000 hp locomotives could not be adopted as a standard unit taking into account the restrictions imposed by track and bridge conditions, the hauling capacity of the locomotives, the impracticability of multiple operations, and flexibility.

Production

A West German locomotive manufacturer solicited their offer by 15 September 1966 which was extended up to 28 September 1966. Both firms submitted their offers. The Tender Committee found the offer of Henschel superior from a technical as well as financial point of view and accordingly recommended its acceptance. The Research, Designs, and Standards Organization of the Railways (K.D.S.O.) also, after technical scrutiny, found the offer of firm B unacceptable. The Committee found that the guarantee terms offered by Henschel were more comprehensive than these of firm B. Henschel quoted for locomotives fitted with Suri transmission as well as Mekydro transmission.

The slightly higher price ( DM 67,500 per locomotive) quoted for the locomotive fitted with Suri transmission over that fitted with Mekydro transmission was found more than justified considering the developmental expenses involved and the expected savings in fuel due to higher efficiency of Suri transmission. The Committee stated that Suri transmission would provide an efficiency of 92% in the final stage as against a maximum efficiency of about 80-83% in the Mekydro transmission and this higher efficiency should result in a corresponding saving in fuel. On the assumption that a locomotive earned (ran) about 400 km per day online and that fuel is consumed at the rate of 4 liters per km therefore, the Committee assessed on a rough basis, the annual saving at about Rs. 20,000 per locomotive even at 5% higher efficiency.

Accordingly, the Committee recommended placement of the order for 6 locomotives fitted with Suri transmission and 2 locomotives with Mekydro transmission on Henschel. The estimated f.o.b., the value of the locomotives was about 10.4 DM (valued at 11.02 million DM - approximately Rs. 2.08 crores). The Railway Board approved these recommendations. An advance letter of acceptance of the tender of Henschel was issued in December 1966.

The contract for the supply of the locomotives was evacuated with the firm on 23 June 1967. The firm had given a guarantee that the locomotive would be built fully in accordance with the specifications and would operate properly. It also guaranteed the proper functioning of Suri transmission. The guarantee was to last for a period of 24 months from the dates of commissioning of the locomotives in India or 26 months from the dates of shipment from Germany or 300,000 km run by each locomotive, whichever event should first occur.

Performance of locomotives

The eight locomotives (WDM-3) arrived in India in the second half of 1970 and were commissioned between August 1970 and May 1971 at Gooty in Southern Railway. The expenditure booked up to August 1975 towards the cost of these locomotives was Rs. 3.37 crores. These locomotives were utilized mainly on freight services on the Guntakal Division of Southern Railway till November 1972, when they were also introduced on express (passenger) service.

In July 1971, Southern Railway Administration reported to the Railway Board that the locomotion had developed defects in the transmission system and converter turbine wheels leading to failures. On the recommendations of the manufacturers' certain modifications were carried out in the torque converter, turbine blades, and mechanical clutches, and thus the trouble in the system was overcome. Nevertheless, the performance of these locomotives had not been satisfactory: the extent of the ineffectiveness of each locomotive ranged from 15.5% to 45.3% (average 27.09%) during the period from the dates of commissioning to the end of April 1973. In April 1973, the Board called for a detailed report on the performance of these locomotives.

* The locomotive availability in terms of hours per day per locomotive in use was less for WDM-3 locomotives as compared to WDM-2 locomotives (manufactured in the country) as indicated in the table below
* On account of lower horsepower (less than 2,600 horsepower), lower axle load (76 tonnes against 110 tonnes of WDM-2 1- motives), and lower converter efficiency at low speeds, the WDM-3 locomotives hauled smaller loads, 23% less in the up direction and 25% less in the down direction, than WDM-2 locomotives, particularly on st8 gradients;
* The maintenance costs were more in the case of WDM-3 locomotives (Rs. 6,851 for cylinder heads) as compared to WDM-2 locomotives (Rs. 2,632 for cylinder heads);
* The locomotive failure rate was higher in WDM-3 locomotives (43,379 km. per failure on the average during 1971-72 to 1974-75) when compared to WDM-2 locomotives (112,893 km. per failure in the same period);
* The fuel consumption of WDM-3 locomotives (both Suri and Mekydro transmissions) was approximately 20 percent more than that of WDM-2 locomotives; (a representative of the manufacturer had stated on 31 January 1973 that the Maybach high-speed engine fitted on WDM-3 locomotives was likely to consume 10% more fuel than a WDM-2 engine on account of pre-combustion chamber configuration)

The various major defects in these locomotive transmissions and engines were brought to the notice of the manufacturers from time to time. The manufacturers advised the Railway Board in November 1973 that, as there had been engine damages on the locomotives equipped with Suri transmission, it would be necessary to operate these transmissions purely hydraulically. The Railway Board agreed to the modifications being carried out. The modifications in essence meant dumping the Suri transmission and converting it into a simple hydraulic Mekydro transmission. This modification in all the locomotives fitted with Suri transmission was carried out between December 1973 and January 1974.

Comparison has sought to be made in the Southern Railway Report of fuel consumption figures between the WDM2 and WDM3 locomotives on the basis of liters per thousand gross tonne-km. This index is only valid when the trailing loads are substantially similar. With the largely dissimilar trailing loads of WDM2 and WDM3 on this highly graded section, the per thousand KM fuel consumption basis would not be relevant.

However, when the two locomotives did haul similar loads, as in the case of the Vrindavan Express between Madras and Bangalore where the speeds attained were higher, the WDM3 locos showed a 4% lower fuel consumption than the WDM2 locomotives. The use of the WDM3 locomotives on passenger trains could not be continued because of the specific project under which they had been procured which limited their use for freight traffic. Later, when permission for the use of passenger services was obtained from KFW, the reliability of the locos had already been impaired on account of the non-availability of imported spares.

By 1990, these locomotives were withdrawn from service.

Former shed

* Gooty (GY): All the locomotives of this class have been withdrawn from service.

See also

* Rail transport in India#History
* List of diesel locomotives of India
* Rail transport in India
* Indian locomotive class WDM-2

References

Notes

Bibliography

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{{Broad gauge locomotives of India , state=collapsed

Bo-Bo locomotives
Railway locomotives introduced in 1970
5 ft 6 in gauge locomotives
Diesel-hydraulic locomotives of India
Henschel locomotives