AY Honors/Model Railroad/Answer Key
A tank car is a piece of railroad rolling stock designed to carry liquefied loads. Many variants exist due to the wide variety of liquids that can be transported. Tank cars can be insulated or non-insulated, pressurized or non-pressurized, and designed for single or multiple loads. Non-pressurized cars have plumbing at the bottom for unloading, and may have an access port and a dome, housing various valving on the top. Pressurized cars have a pressure plate, with all valving, and a protective cylindrical housing (dome) at the top. Loading and unloading are done through this opening.
Insulated cars (which may also incorporate heating or refrigeration systems) are used when the contents must be kept at a certain temperature. For example, the Linde tank car depicted below carries liquified argon. Cars designed for multiple loads have internal bulkheads to separate the contents. Non-pressurized multiple load cars are easy to spot as each compartment has an expansion dome.
In some countries, such as the United Kingdom, Ireland, and New Zealand, tank cars are called cylinder wagons or tank wagons.
History
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The narrow domes on these East Tennessee and Western North Carolina Railroad tank cars mirror the designs of the first all-steel units.
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Texaco, Inc. (TCX) #723, a single-dome tank car designed for transporting gasoline, passes through Amarillo, Texas on April 4, 1936.
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This double-dome tank car has two separate interior tanks, which allow different products to be transported in the same car.
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This unusual three-dome tank car has an oversized center dome.
Tank cars have always been specialized pieces of equipment. The interior of the car is usually lined with a material to isolate the car's structure from the contents, such as glass. Loading a liquid into a car that is designed to carry something else is unwise and sometimes dangerous. Even after a thorough cleaning, traces of the previous contents may remain. Loading a pesticide-carrying tank car with cooking oil is one example. The cooking oil will at best be unpalatable and at worst become toxic.
As a result of this specialization, tank cars have always been "one-way" cars. Other cars, like boxcars can easily be reloaded with other goods for the return trip. Combinations of the two types were attempted, such as boxcars with fluid tanks slung beneath the floors. While the car could certainly carry a load both directions, the limited size of the tanks made this style unsuccessful.
Because of their one-way nature, tank cars are simply dead weight half of the time, making them unappealing to major railroads. Virtually all tank cars are owned by companies serviced by railroads instead of the railroads themselves. This can be verified by examining the reporting marks on the cars. These marks invariably end in X, meaning that the owner is not a common carrier. Template:Sect-stub
Timeline
- 1865: Flats with banded wooden tanks mounted on top are employed for the first time to transport crude oil from the fields of Pennsylvania.
- 1869: Cast iron tanks (with an approximate capacity of 3,500 gallons per car) replace wooden tanks.
- 1888: Tank car manufacturers sell units directly to the oil companies, with capacities ranging from 6,000 gallons to 10,000 gallons.
- 1903: Tank car companies develop construction safety standards; more than 10,000 tank cars are in operation.
- 1915: A classification system is developed by the tank car industry to ensure the correct match of product being shipped to car type. Some 50,000 tank cars are in use.
- 1920: Welding technology replaces riveting in tank car construction, enhancing the safety of cars.
- 1930: 140,000 tank cars transport some 103 commodities (in addition to oil) to market.
- 1940s: Virtually every tank car is enaged in oil transport in support of the war effort.
- 1950: Pipelines and tanker trucks begin to compete for liquid transport business.
- 1963: The Union Tank Car Company (UTLX) introduces the "Whale Belly" tank car.
Specialized applications
Gas transport
Milk cars
A milk car is a specialized type of tank car designed to carry raw milk between farms and processing plants.
Pickle cars
A pickle car is a specialized type of tank car designed to carry pickles.
Tanktainers
A tanktainer is a specialized type of container designed to carry bulk liquids on standard intermodal equipment.
Vinegar cars
A vinegar car is a specialized type of tank car designed to transport vinegar.
"Whale Belly" cars
In the early 1960s, the Union Tank Car Company (UTLX) introduced a series of "whale belly" tank cars which offered increased capacity over the standard cars of the day. Capable of carrying 33,000 gallons (as was the case with Citco #31084) to as much as 50,000 gallons, the largest of these cars (such as UTLX #83699, now on display at the Galveston Railroad Museum) first hit the rails in 1963 and remained in service for over 20 years. These behemoths were 89 feet in length and weighed 175,000 lb. empty; the cars, which rode on four 2-axle trucks to distribute the additional weight, were used to transport such diverse substances as liquefied petroleum gas (LPG) and anhydrous ammonia.
References
- Template:Web reference
- White, Jr., John H. (1993). The American Railroad Freight Car. The Johns Hopkins University Press, Baltimore, Maryland. ISBN 0-8018-5236-6.
External links
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Template:Freight cars
ja:タンク車
de:Kesselwagen
eo:Kanistra vagono
