Unit train

The unit train is the most common form of long-distance coal transportation. A unit train is group of railcars that operate in a dedicated shuttle service between a coal mine and a power plant. 

FIGURE 6.24 Stone marker showing the position of the overland trail (seen to the right of the marker). 

The cost of shipping coal by train is often more than the mining costs. Using a barge or ship to move coal is a lot less expensive. In the United States, there are 25,000 miles of waterways, but not enough to reach all destinations in the country. To reduce transportation costs, power plants are sometimes constructed near coal mines. 

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Solids. Increasing use of bulk cars, especially of covered hopper cars, has accompanied the expansion of the tank-car fleet. The principal drawback of bulk cars is the requirement for limited use, specialized cars, which necessitates a large investment. However, if such investment can be justified, the cost of transportation for dry bulk materials ia hopper cars usually is less than those for goods ia shipping containers. In many instances, such cars are used in closed-loop service that is, they shuttle in unit trains between filling and discharge points. Similar equipment is also used in specialized highway vehicles whose tmck bodies can incorporate dump hoppers and built-in conveyors. 

Coal pipelines have been built in countries such as France (8.8 km), and Russia (61 km), and pipelines are also used for transporting limestone, copper concentrates, magnetite, and gHsonite in other parts of the world. The first coal pipeline, built in Ohio, led to freight rate reductions. The pipeline stopped operation after introduction of the unit train, used exclusively to transport coal from the mine to an electric power generation station. 

Keep in mind rail tariff breaks for numbers of cars in a string so that the ability to handle the required numbers can be provided. If the operation is large enough, as for large coal mining operations, unit trains (100 cars) are used. 

Rail-transported coal is typically moved in unit trains that operate in dedicated shuttle seivice between a mine and a destination. Unit trains operating in the western United States and Canada consist of 100 to 120 lightweight aluminum railcars cainying upward of 121 tons (110 tonnes) of coal apiece, or more than 14,000 tons (12,700 tonnes) per train. In the 1990s, distributed power (DP) came into widespread use in the western United States. In this system a remotely controlled engine is put into the middle of a train, allowing greater traction and control of train motion. DP trains can consist of 135 cars and are the most efficient method of rail transportation of coal. 

Notes Upper curve depicts en aver eye rate applying to many chemicals shipped in 40.000 lb. lots. The "low-bulk" curve represents approximately the cheapest rates available for chemical commodities shipped in bulk, except for the few cases where unit train rates have been established. Actual freight rates are not predicted by the curves because rates for specific chemicals and movements are normally negotiated between the carrier and the shipper. 

Unit trains can pose problems to small manufacturers who do not have the volume to use them. This effectively gives the big producer a price advantage this is frowned upon in Washington. In 1969 the Dow Chemical Company, which was using unit trains to deliver coal from West Virginia to Midland, Michigan, was accused of violating railroad tariff rate. It was claimed Dow paid less than published tariff rates. In an out-of-court settlement Dow paid 350,000 in claims. ... 

Unit Trains Trim Acid Costs, Chemical Week, Mar. 15, 1969 p. 101. 

At identical variable number, the overlay-based model outperforms its overlay-independent equivalent training RMS = 0.712 (pICso units), training = 0.712, validation RMS = 0.698, training = 0.724. ComPharm field descriptors therefore appear to have a better predictive power than pairwise pharmacophore feature counts alone. 

If liquids are controlling, the residence time varies from 2.5 to 5 min, half full, depending on water content. With this vessel design parameter In mind, reference should be made to the expected production decline and produced water cut time profiles. A decision can then be made based on calculation of residence times If 75% or 50% unit trains should be designed For the problem illustrated, 2 x 73% units would be selected to permit flex iblllty (Table 4). 

Fig. 15. Unit train is loaded with coal as it passes through base of storage silo...

Although the Ohio line operated successfully, transporting 7 million tons (6.3 million metric tons) of coal, some unexpected operating problems had to be resolved. Much investigation was conducted with variables, such as size consist and slurry concentration and the resultant effect on slurry stability. After 7 years of operation, the line was shut down in 1963, when the unit train concept resulted in much lower freight rates on signilicantly higher amount of coal movement. 

It follows from economical comparison that coal-log pipeline is cheaper than truck transport for distances longer than 65 km and pipe diameter D = 200 mm. For D = 500 m even for distance over 25 km. Compared with railway, the transport cost is on the level of unit trains. For large quantity of coal it could be even less. Another advantage is given by fact that length of pipeline is usually at least about 30 % lower than that of the railway. From environmental protection point of view, capsule pipeline, similarly as slurry pipeline, is dust free and noiseless. In spite of these advantages the utilisation of coal-log pipeline system could expect only for transport of coal from new mines to power stations, especially in mountains areas without railways and highways or in heavy populated and industrial areas, where railway is overloaded. 

The lot of coal must first be defined (e.g., a single truck, about 20 tons a barge, about 1500 tons a unit train, about 10,000 tons or a ship cargo, about 100,000 tons). 

Coal prices delivered to manufacturing sites on the East Coast, the Mid-Continent (Illinois), the Gulf Coast, and the West Coast were estimated and the transportation cost in unit trains was added to the estimated mine-mouth coal prices to provide estimated prices of coal delivered to the manufacturing sites as are shown in Table 9. 

A discounted cash-flow analysis of the system was made using conservative financing assumptions. These included 100% equity, 12% return on investment, and a plant life of 20 years plus a construction time of five years. Strip-mined western coal was priced conservatively at 15 per ton. This is a reasonable price, for example, for coal delivered from Gillette, Wyoming by unit train to a plant serving the Chicago area (mid-1977 prices) alternatively, a mine-mouth plant site would obtain coal at lower prices, but product transportation costs would be higher. 

Another important factor in the availability of coal is an adequate supply of transportation facilities, particularly railroad hopper cars. There is little or no storage at the mines except for unit train shipments, so mines generally cannot operate without an adequate supply of coal cars, wluch determines the number of days of active mine operation. Because of the close a Bnity of coal and rail transportation, the deterrents to expanded coal productive capacity also affect the development of new transportation facilities. Of considerable importance in the future will be an increase in the number of unit trains, which help to reduce transportation costs and the potentials for more coal slurry pipelines and for mine-mouth generating plants for the extra-high-voltage transmission of coal-produced electricity. 

Although nearly 40% of the known recoverable coal reserves of the United States are low in sulfur content (less than 1 lb sulfur/MM Btu), these reserves are concentrated in the Rocky Mountain Region, remote from the eastern industrial demand centers. At current unit train costs of about 4fS/MM Btu per 1(K) miles, an incremental transportation cost of 40f to 80jS/MM Btu would be incurred. 

The MEU(SOC) units receive both individual and unit training prior to deployment, they participate in field exercises, and they are then certified as ready. In addition to this unit, all sailors and Marines in the MEU(SOC) are qualified in NBC individual protective measures before they deploy. While this training meets current requirements, there is an ongoing effort within the Marine Corps to enhance the training content, particularly with regard to biological warfare defense. This capability is resident in the MEU(SOC) units deployed in support of Operation Enduring Freedom. 

Navy readiness for chemical and biological warfare defense needs improvement in the following areas establishment, validation, and enforcement of standards, performance and material condition of installed protective systems, availability and condition of protective equipment, shelf life of medical countermeasures, field exercise programs, basic and unit training, and readiness reporting. 

Kl. Kanabrocki, E. L., Scheving, L. E., Halberg, F., Brewer, R. L., and Bird, T. J., Circadian variations in presumably healthy men under conditions of peacetime army reserve unit training. Origin Life 4, 258-270 (1973). 

Unit Trains. Coal in unit trains is already being carried to the chemical industry. In the 1970s other raw material unit train movements may well follow. We expect an increase in unit train movements of chemical products—such as the proposed unit train movement of anhydrous ammonia from the Gulf Coast to the com belt. These movements will take place from remote raw material sources to plants as well as from plants to distant concentrated markets. Trainloads of semifinished, in-process chemicals will probably move between a company s plants or to customer plants. 

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