DOT105 and 112 cars are high-pressure cars used to transport hazardous materials under pressure or those hazardous materials for which the DOT or the shipper require the additional protection of a safer car.
(Low Pressure Cars)
DOT111 low-pressure cars are used to transport both hazardous and non-hazardous materials. Tank test pressures for this car will be 100 psi or less. Safety features common to tank cars carrying hazardous materials include double shelf couplers and head shields. Thermal insulation — either sprayed on or jacketed — may also be present when flammable liquids or gases are transported. A dent in a jacketed car may be separated from the main body of the tank by up to 12 inches of insulation. These cars make up over 70 percent of the tank car fleet. Typical shell thickness of these cars is 7/16 inches. They usually have a low profile manway on the top of the car with most of the loading and unloading fittings being found in the general area of the manway. They may be equipped with a bottom outlet valve for loading and unloading. The safety relief device may be a safety vent equipped with a frangible disc which will function only once and then remain open or a spring loaded safety valve which will function to relieve pressure and then re-close to enable it to function again if necessary. Some cars may be equipped with a safety valve/safety vent combination device. Non-pressure cars may or may not be jacketed or insulated and may have exterior or interior heater coils. Steam lines may be connected to these heater coils at unloading racks because some products such as molten sulfur and asphalt not be used for the transport of flammable or poisonous liquids. It is important to remember that these cars, while in service, can have significant internal pressures. When initially opened, fittings and valves will have considerable backpressure and can spray product if not properly operated.
DOT105 and 112 cars are high-pressure cars used to transport hazardous materials under pressure or those hazardous materials for which the DOT or the shipper require the additional protection of a safer car. DOT105 cars are used to transport liquefied gases and high hazard or environmentally sensitive materials. They are insulated with foam, fiberglass, ceramic fiber or cork and have an exterior metal jacket to protect the insulation. They can be distinguished from low-pressure cars by the fact that all of the loading and unloading fittings are in one location on the top of the car and are covered by a protective housing. These cars are equipped with a spring loaded safety valve which is set to function at 75 percent of the test pressure of the tank. Bottom outlets are not permitted nor are any fittings outside of the protective housing. These cars are typically used to transport chlorine, carbon dioxide, sulfur dioxide, anhydrous ammonia and LPG’s. DOT112 cars are used to transport liquefied gases and high hazard or environmentally sensitive materials. When flammable gases are carried, head shields and thermal protection will be present. Tank cars used to transport carbon dioxide and certain other liquefied atmospheric gases are also equipped with pressure regulators that are designed to relieve internal pressure during transportation. Venting product to the atmosphere is normal for these cars.
The primary function of the boxcar is to transport commodities and products requiring protection from the weather. In addition to the boxcars used for general freight, other cars have been designed for shipping such freight as automobile parts, lumber, grocery products, appliances and some bulk materials. Hazardous materials may be transported in boxcars in bottles, boxes, drums or intermediate bulk containers. The major hazard from boxcars is the shifting of lading during a derailment. Large, unstable loads, as well as hazardous materials, may be encountered.
The refrigerator car, similar in appearance to the boxcar, is essentially an insulated car that has been designed to transport commodities that require low or specific temperatures. An additional potential from a refrigerator car is the possibility of a fuel spill. The generator that runs the cooling plant may have a diesel fuel tank with capacities as high as 500 gallons. Typical refrigerator cars can be satellite controlled and may turn on or off at any given moment.
The flatcar is a general-purpose car built without sides. Flatcars are manufactured in various shapes and sizes to meet the specific requirements of shippers. The movement of highway trailers on flatcars (TOFC) and intermodal containers (COFC) is the most likely way hazardous materials will be encountered on flatcars. TOFC shipments will usually involve non-bulk containers such as drums and bottles. COFC shipments can either be bulk shipments as in the case of tank containers or non-bulk as in the case of box containers.
Gondola cars are built in various sizes and capacities to meet shipper requirements. Cars with lengths and capacities as much as 60 feet and 100 tons are available. Cars have been designed to accommodate oversize loads, both as to length and overhead clearance, and to permit side or bottom dumping. They may be equipped with racks for special commodities or covered to provide weather protection. A common use for gondola cars is the transportation of contaminated soils and hazardous wastes.
Due to the emphasis of bulk movement of freight by rail, hopper cars constitute the largest number of freight cars among railroad equipment. Hopper cars have been designed with powered door operating devices, some of which are completely automatic thus making them self-unloading. Hopper cars can be divided into two categories; open-top hoppers and covered hoppers. A subgroup of covered hoppers is the pneumatic hopper, which can be pressurized to a level that allows the load to be pushed out or flow. Covered hoppers should not be under pressure during shipment or movement. Oxidizers in powder or granular form are commonly transported in covered hoppers. Fertilizers, pigment powders and other solid materials represent potentially environmentally sensitive materials that may be transported in hopper cars.
An autorack, also known as an auto carrier is a specialized piece of railroad rolling stock used to transport automobiles and light trucks, generally from factories to automotive distributors. Amtrak also uses them on its Auto Train route, which carries passengers and their vehicles. Railroads of today are still grappling with the problem of loading more and larger vehicles onto autoracks. One popular solution is to create a double-length car that is articulated over a single middle truck so that each half of the car is about the same length as a conventional autorack. These cars, which can be seen in operation on many of the railroads in the western United States, are brand named AutoMax cars. These cars are 145 feet long and 20 feet tall. They feature adjustable interior decks to carry up to 22 light trucks and minivans. The railroads became the primary long-distance transporter of completed automobiles. Using the enclosed tri-level autoracks, they were able to provide both lower costs and greater protection from in-transit damage — such as that which may occur due to weather and traffic conditions on unenclosed semi-trailers. When the railroad companies went from the open autoracks to the enclosed, they were able to reduce freight damage claims. The enclosed rail cars prevented the autos from getting damaged from falling or thrown rocks, bullets and other forms of vandalism. They also stopped the theft of autos and parts from autos and kept hobos from living in the automobiles. A fire in these cars presents a very difficult situation as the cars can only be opened through the clamshell doors at the ends and cannot be easily unloaded. It is very difficult to gain access through the side panels as well.
A unit train is a railroad train in which all of the cars making it up are shipped from the same origin to the same destination, without being split up or stored en route. This saves time and money, as well as the hassle, delays and confusion associated with assembling and disassembling trains at rail yards near the origin and destination. It also enables railways to compete more effectively with road and internal waterway transport systems. However, unit trains are economical only for high-volume customers. Since unit trains often carry only one commodity, cars are of all the same type, and sometimes the cars are all identical apart from possible variations in livery. Unit trains are typically used for the transportation of bulk goods. These can be solid substances such as ballast, gravel, iron ore, coal, coke and steel. Bulk liquids are transported in unit trains made up of tank cars containing crude oil, mineral oil products, ethanol and molten sulfur. Food, such as wheat, corn, fruit juice and refrigerated food is also carried in unit trains. Other examples include intermodal containers, cars, aggregate, potash, taconite, mail and materials bound for recycling centers.
Locomotives represent an ever-present source of potential hazards for emergency responders. The modern diesel-electric locomotive is a 6000 horsepower behemoth that weighs in at 420,000 pounds and can carry up to 5600 gallons of fuel, 380 gallons of cooling water and 410 gallons of lubricating oil. This in itself can pose significant problems if the tank is ruptured in an accident. In addition to the potential for a fuel spill, locomotives can pose an electrocution hazard if they are not properly shut down. Diesel-electric locomotives use large diesel generators to provide electric power to traction motors. These traction motors provide the motive power to move the locomotive and in turn the train. These generators can develop upwards of 600 volts of DC power or 23000 volts of AC power at 800 amps. Clearly coming into contact with an energized circuit of this magnitude would cause serious injury. Because a locomotive is a complicated piece of machinery, emergency responders should only attempt to shut down the locomotive using the fuel shut-offs. Any other measures should only be attempted by trained personnel.
There are three emergency fuel shut-off switches on all locomotives. Two of these switches are located on the outside of the unit, directly above the fuel tanks. The internal emergency fuel shut-off switch is located in the engine’s cab directly behind the engineer’s control stand. These switches are activated by pressing the button. This causes a solenoid valve at the top of the fuel tank to close. Once this valve is closed, all fuel flow to the diesel engines will cease. The engines will then shut down within one minute. Keep in mind that the locomotive may remain energized after the diesel engine is shut down.
Most military trains are escorted by and/or under close watch by military forces or resources as well as railroad police and agents and other law enforcement entities within the United States. Military incidents would fall under military control and would not be public knowledge for very good reasons. Should a railroad incident involving military assets occur in your jurisdiction, you may not even be informed of it depending upon the severity. If you are notified of it, it may just be a courtesy notification. If your assistance is required, remember that the military will be in charge and not the local emergency responders. This could easily be declared as an Incident of National Significance, ensuring that the Federal Government is in control.
Nobody Tells Me Anything But...
A common theme in many of the articles addressing actual train derailments or the possibility of a derailment occurring in a community is the fact that the vast majority of fire departments have no idea what is being transported through their jurisdictions. What’s worse is the fact that they blame the railroad for this! “The railroad never tells us anything...” they say. This is inexcusable! Get out there and find out what is being transported through your community.
Look at the Tier II Reports — Emergency Management can help you here — that companies are required to file by Federal regulations. These will tell you what companies use in your jurisdiction and how much they use. If they use it, it has to come into your jurisdiction somehow. A Transportation Commodity Study will tell you what is transported through your jurisdiction, whether it is used there or not.
Preplans will give you the same information, and more, as the Tier II Reports. The Local Emergency Planning Committee or LEPC — of which your fire department should be a member — and the State Emergency Response Commission (SERC), should also be able to give you some information.
Finally, get out there and watch some trains! This is excellent training. Watch a train with your Emergency Response Guidebook and look stuff up! Look up the placards by the UN number. Look up the chemicals in the dedicated rail cars. Determine a course of action for pressure and non-pressure cars based on the car’s silhouette and a guide page. After a couple of these training evolutions, you now have a better idea of what travels through your community and you’ve sharpened your skills with the ERG.
It is impossible to prepare yourself to deal with a railroad incident of any magnitude just by reading a few journal articles. You must take advantage of other resources out there such as self study classes and Whistle Stop Tours provided by numerous railroads. You will also find railroad related topics at many of the local and national firefighter conferences. You may never need to respond to a railroad incident, but it is imperative that you have the tools just in case you are called to respond.
Mark Schmitt is Captain/Hazmat Specialist for the Greensboro Fire Department in Greensboro, N.C., and a veteran of over 20 years in the fire service. The majority of his career has been spent in special operations. He is a graduate of the National Fire Academy’s Executive Fire Officer Program and holds a Master of Public Administration in Emergency Management. Schmitt has taught numerous hazardous materials courses for the Greensboro Fire Department, local community colleges and the North Carolina Office of the State Fire Marshal in addition to serving on several hazardous materials related committees at the local and state level.