BULK TRANSPORT OF MILK BY RAIL

Historian T.H. Collingwood once stated, “The ultimate aim of history is human self-knowledge. The value of history is that it teaches us what man has done, thus what man is.” Understanding our past is essential to grasping our present.

The history of dairying in India stretches back millennia, but its modern evolution is closely tied to wartime economies, technological advancements, and aspirations for freedom. The presence of Allied forces in India during World War I and II, particularly in Bombay, created a demand for butter and quality milk. This necessity led to the introduction of cream separators in Keda district in the 1930s, which marked a pivotal moment in India’s dairy industry.

The genesis of Amul, India’s largest FMCG brand, is linked to the freedom movement and the leadership of Shri Tribhuvan Das Patel, inspired by Sardar Patel. Morarjibhai Desai noted Patel’s role in forming the Kheda District Milk Producers Union, highlighting the significance of General Manager Verghese Kurien from the outset.

Dr. Kurien, influenced by his mentor Shri T.K. Patel, utilized his technical and managerial skills to strengthen the Kheda Jilla Dudh Utpadak Sahakari Sangh and expand cooperative unions across Gujarat. He transformed this union into Amul and conceived Operation Flood, a groundbreaking initiative.

Operation Flood I, II, and III not only made India self-sufficient in milk production but also established it as the world’s largest milk producer. The small town of Anand in Gujarat, home to Amul and the National Dairy Development Board, became the Milk Capital of India. Dr. Kurien, who arrived in Anand in 1949 and lived there until his passing, spearheaded waves of technological and managerial innovations that modernized and propelled the Indian dairy sector.

One significant innovation was the bulk transportation of milk by rail, which was introduced before Operation Flood. However, the expansion of tanker sizes, advancements in cooling technology, and the distances covered were realized during Operation Flood, making the concept of a National Milk Grid a reality. I was present in Anand when Prime Minister Shri Rajiv Gandhi flagged off bulk milk tankers to transport milk from Anand to Kolkata, over 2,051 kilometers away. This moment became a landmark in the history of modern dairying in India.

BULK TRANSPORT OF MILK BY RAIL

BY V. ANAND DEPUTY DIRECTOR/RDSO

(Published in “Indian Railways” magazine August 1978 edition)

Prior to Independence, the Dairy Industry in India was rudimentary. With the pace of industrialisation and consequent urbanisation picking up, the transport, storage and processing of milk assumed greater importance. For obvious reasons, the production of milk is confined to rural areas. If proper transport and storage facilities are not available, the rural milk producer is unable to market his surplus during the “flush” season. On the other hand, the rural milk producer has neither the capacity nor the technical know-how required for the setting up of storage, preservation and processing facilities. Thus, there is no incentive for the milk producer to increase the per capita production of milk unless a way is found to capitalise on the surplus production.

India has the largest number of cattle in the world. Paradoxically the per capita consumption of milk is amongst the lowest in the world. The value of milk as an item of food needs hardly any emphasis. Milk is an indispensable supplement to the predominantly vegetarian diet of the majority of Indians. Increase in the per capita consumption of milk in the country is bound to lead to overall improvement in health and well-being.

It is to the credit of Indian pioneers in the cooperative dairy movement that they recognised this important aspect of dairy farming. Against scepticism from the advanced countries, whose dairy technology is primarily based on cows’ milk, our dairy technologists have successfully managed the preservation and processing of buffalos’ milk and its conversion into other articles of food.

The importance of speedy transport of milk, which is a highly perishable commodity, from the production centres to the processing centres and thence to the consumer was recognised quickly by the cooperative movement in Gujarat which showed the country what could be achieved in the field of dairy management encompassing both animal husbandry and milk technology.

The Railways have an important role to play in the bulk transport of milk in view of the speed, safety and reliability of railway operation as compared with other modes of surface transport. The design development of milk tank vans for the bulk transport of milk by rail is briefly surveyed in this article.

The bulk transport of milk has been a post Independence phenomenon; until then most of the milk was being moved directly from the producers to the processors/consumers in canisters. Suburban trains of this day have compartments earmarked for this form of transport of milk. Some of the larger dairies also used to get milk in cans loaded in insulated vans. These vans are similar in construction to parcel vans. The milk was usually frozen after being poured into the cans. A few of these insulated vans are still running on the Indian Railways but their use is being phased out.

As the volume of milk traffic increased, it was realised that the existing methods would be totally inadequate, to handle it. The various dairy development authorities who were seized of the problem of transporting milk in bulk realised that bulk transport of milk has certain distinct advantages from the point of view of the carrier as well as that of the consignor/consignee. Bulk transport eliminates manual handling thereby ensuring that the milk is processed under completely hygienic conditions. The losses due to spillage are also less. Moreover, the nuisance caused by spilt milk is also obviated. It is also axiomatic from thermodynamic principles that the rate of heat gained for milk in bulk is less than that for the same milk stored in a number of small cans due to the reduction in the surface area for a given volume of milk. From the carriers’ viewpoint, bulk transport offers a better payload-to-tare ratio for the vehicles. Individual accountal of cans is also obviated and thereby claims on account of the mishandling/misdirection of cans is automatically eliminated.

In the early stages, the Dairy Industry in India was being assisted by more advanced countries in the field, such as New Zealand. Simultaneously with the modernisation of the milk processing equipment, the bulk transport of milk in tanks also acquired greater impetus. Under the Colombo Plan, some milk tanks were to be supplied by New Zealand and the Indian Railways were required to design suitable vehicles to carry these tanks. After joint consultation with the dairy development authorities and the representatives of the FAO, the complete design of milk tank vans was evolved. This design aimed at optimising the carrying capacity of the vehicle commensurate with the requirements of axle loads and the moving dimensions of the Indian Railways as well as the higher speed potential necessary for movement by passenger trains.

A new era was ushered in the bulk transport of milk with the commissioning of eight such milk tank vans for the Greater Bombay Milk Scheme, Government of Maharashtra. The milk tank vans as finally built consist of two 3,000 gallons tanks mounted on a skeletal underframe carried on IRS type of bogies. The two tanks have a total carrying capacity of 27,276 litres, thereby giving a payload of 27.4 tonnes, the tare weight of the milk tank van being 31.2 tonnes. This may be compared to the earlier bogie insulated milk vans in which the milk was carried in cans. In these vans having a tare weight of 32.9 tonnes, only 15.8 tonnes of milk, could be carried.

The quest for higher speed for these milk tank vans, however, eluded immediate results. The higher pay load to tare ratio which makes it difficult to control the buffer heights within the schedule of dimensions and the inherent drawbacks of the IRS type of bogies precluded the further development of this type of milk tank vans for higher speeds. However, these milk vans are still doing yeomen service running attached to passenger trains with a maximum permissible speed of 75 km/h. Likewise four-4 wheeler and two bogie milk tank vans built by the South Central Railway for the Andhra Pradesh Integrated Milk Project are also running between Vijayawada and Secunderabad at a maximum speed of 75 km/h.

With the advent of ICF bogies which incorporated coiled springs as well as hydraulic damping both in the primary and secondary suspension stages, it was felt that this type of bogie offered prospects of higher speed potential. Development work was undertaken by RDSO on behalf of Government of Maharashtra and a design was evolved for mounting a single 9000 gallon insulated tank (supplied by New Zealand) on a shorter underframe carried on ICF type bogies. However, in this design, the secondary stage damping was through friction dampers. This milk van also has a unique braking system by which two cylinders work when the tank van is empty and four vacuum cylinders come into action when the milk tank van is loaded.

Here, it would not be out of place to make a brief mention of the milk tanks themselves. Although such milk tanks were originally imported, indigenous know how has since been built up. Due to the peculiar properties of milk, utmost care is required in ensuring high standards of hygiene. The tank consists of an inner stainless steel barrel, the inside surfaces of which have been ground to a mirror finish, supported through semicircular rings on an outer tank barrel of mild steel. The intervening space is filled with insulation. Cork at one time was very popular but the modern trend is to use expanded polymers such as “Thermo cole”. No baffles are permitted inside the stainless steel tank and other accessories such as ladder, cleaning devices, delivery pipes, manhole covers are made of mirror finished stainless steel. The filling is done through a manhole cover from the top which can be screwed down and is further secured by a lid which can be padlocked and sealed. Delivery boxes which are provided on either side of the tank are fitted with stainless steel valves. The delivery boxes can be locked and sealed.

With this arrangement the possibility of milk spilling or leaking out or for that matter being pilfered, is obviated. Due to the 150 mm thick insulation, the milk which is usually loaded after being chilled to a temperature of about 4o  C rises in temperature  by  about  only  2oC  in  24  hours.  Indian  Standards  Institution  has  also  drawn  up  rigid  specifications governing these milk tanks.

The initial lot of 10 milk tank vans of 9,000 gallon capacity (40,914 litres 42 tonnes) was placed on line in 1968. These offer 50 per cent increase in carrying capacity as against the earlier lot of bogie milk tank vans with hardly one tonne increase in tare weight. Thus the pay load to tare ratio was further increased from 0.88 to 1.28.

Meanwhile the dairy industry in India was being developed at an accelerated pace through the efforts of the Indian Dairy Corporation and the National Dairy Development Board. They launched what is popularly as “Operation Flood Programme” which was designed to create a “white revolution” all over India. One of the objectives was transporting surplus milk from the rural dairy farms. This project received assistance from the World Food Programme and it was decided to acquire 30 BG tank vans. These are similar in construction to the earlier lot of 10 milk vans except that the payload was rationalised to 40,000 litres and the tank barrel was of indigenous design and construction. The cradles on which the tank barrel is mounted were also rationalised on Indian Railways’ standard design.

One such milk tank van was subjected to oscillation trials in 1976 and with improvements in the suspension namely provision of hydraulic shock absorbers and suitable springs, it was found that the riding was satisfactory up to the test speed of 110 km/h.

Meanwhile attention was also paid to the MG system especially in the Western Region where dairy farming was making great strides. The Delhi Milk Scheme acquired 5 milk tank vans for MG operation. These milk tank vans were designed by RDSO and were placed on line in October 1976 on the Delhi Bikaner route. A single tank of 21000 litre capacity is carried on a skeletal underframe mounted on ICF type bogies. Although the design originally envisaged IRS bogies, further development was pursued with ICF type bogies on account of the latter’s greater speed potential. A fact which weighed heavily in the minds of the designers was that irrespective of the booked speeds, MG passenger trains are permitted to run at a maximum speed of 75 km/h. Thus any milk tank van designed for MG operation would have to have a speed potential of 75 km/h. even for running with the slowest passenger train, in view of the fact that the maximum goods train speed is very much lower, i.e. 50 km/h.

Accordingly, a number of novel features were incorporated for the first time in these milk tank vans. Centre pivot loading was adopted in preference to the conventional ICF side bearer loading on account of the nature of the construction of the underframe. Two stage braking through the two vacuum cylinders operating on the same brake shaft was adopted with a load empty changeover device similar to that fitted in BOX wagons. Direct Admission Valves have been fitted. With these features, the optimum brake power has been ensured. A remarkable feature of the suspension is the progressive springing used in the secondary stage which enables good riding to be achieved under varying conditions of loading. Tank barrels were designed and built indigenously.

One such milk tank van was subjected to oscillation trials and it exhibited satisfactory riding up to the highest test speed of 85 km/h. It is expected that these milk tank vans will, in the near future, start operation with mail/express trains.

Meanwhile, the National Dairy Development Board and Indian Dairy Corporation are going ahead with “Operation Flood II” by which milk production is expected to be increased immensely. Action is on hand to acquire more milk tank vans to help in realising the objectives of this operation.

Conclusion:  Dairy technology in India has made rapid strides in the past few years and simultaneously associated technological infrastructure has also been built up. Speedy and reliable transport of milk is an indispensable part of the totality of the dairy technology. The Indian Railways’ design development of milk tank vans will go a long way in meeting the demand for the bulk transport of milk thereby paving the way for the “White Revolution” which has started to sweep the country.