Most modelers are at least familiar with the operations and railcars of many industries. Logging, mining, steel making, manufacturing – these are all well supported in hobby texts and magazines and they pop up frequently on model railroads. The giant umbrella of “the chemical industry” is a little less obvious. Although it includes many different traffic sources, railroads often group all of these industries into the same family as their operating needs are similar.
Not only are the needs of many different chemical companies similar, in today’s world of big corporations, many are different divisions of the same large company. And since different products are often byproducts of other processes, these plants are often located in close proximity to each other. A good example of this is with petrochemicals – that is chemical products that all come from oil.
While fuel and heating are the most obvious and common uses of oil, the refining process produces many other gasses which are used in everything from plastics to pharmaceuticals.
Consequently, it is common to find many related industries clustered near refineries. The “Chemical Coasts” around Houston, Texas and in New Jersey and Delaware are good examples. Trains headed to and from these points will almost certainly carry a lot of traffic in covered hoppers and tank cars. So for the modeler, a chemistry degree is not always necessary to build an accurate picture of railroad operations around the industry.An advantage to modelers is that many cars do display information that can be helpful in identifying the commodities carried inside for the help of emergency responders. Non-hazardous materials are also commonly displayed on the sides of cars to prevent reloading with different materials. With this basic knowledge you can do some quick research to figure out what it is used for. A little research reveals just how important these industries are to modern life as we know it.
Without getting into great specifics, there are two types of railcars most associated with chemical traffic. The first thing most modelers think of is tank cars. Tank cars carry liquid chemicals in many varieties and are often quite specialized. Heavier cars are carried in smaller cars. Some feature insulation and heating coils. Others have special vents, interior linings and unloading attachments. Once assigned to a particular commodity, tank cars can not be switched to a different load without an extensive cleaning.
Dry chemicals are carried in bulk aboard covered hoppers. Again, these come with a variety of sizes, shapes and features based on the specifics of the load. Plastics are one of the more common loads today and travel in very large covered hoppers. Powdered chemicals often requires with pneumatic attachments to assist in unloading. Most of these cars are painted a fairly bland gray today, but more colorful cars can be seen and were more common in the 1960s and 1970s.
Not every chemical car is a hazardous load. And not all haz-mats are equally dangerous, nor can they be dealt with the same way. Ethanol for example, while highly flammable, poses less of a risk to wildlife during a spill than gasoline or even milk. (Milk is considered a hazardous material in bulk as it depletes oxygen levels and promotes bacterial growth in water and can kill water life.) Today, cars carying hazardous materials are required to display information on placards and often on the tank itself as to its contents. Railroad operators also keep careful track of a train’s loads and empties on manifest sheets. Some cars are still considered dangerous even when empty.
Railroads generally offer the safest mode of transportation for these materials however, so placarded cars are quite common. Some loads require special handling instructions. For example, today many hazardous tank cars can not be placed next to a locomotive, caboose or a car with a load that could shift and puncture the tank. These extra handling instructions can mean extra work for the real railroads, but offer a chance for more operating fun on our layouts.
You may not always be able to pronounce some of the compounds you’ll find in tank cars and covered hoppers, but that doesn’t mean they can’t become an important part of your railroad knowledge and fun. You may find that this is just one more way in which learning about trains helps promote a much broader interest in the world around us.