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What you need to know about the Rail Tank Car

We are all used to seeing lines of rail tank cars being transported on the railroad. But do you know what the information on each truck means and what to do if there is an accident? The good news is that the information is all there for you, so let’s first take a look at the rail tank car markings and fittings which are visible from ground level. 


DOT Tank Car Markings

DOT Tank Cars all have a set of unique markings printed on the side of the tank,   in the same way as every automobile has a registration number and specific code. The Reporting Mark is the equivalent of a license plate. This is printed on the sides and the rear and the front end of the tank and you can find out everything about its hazardous contents by calling the railroad company and quoting the reporting mark because all tank cars are tracked and recorded on each journey.

Below the reporting mark on the side of the truck is the weight information. LD LMT refers to the maximum weight when fully loaded. LT WT or lightweight is the empty weight of the tank car. 


The Flash Code

All DOT railcars transporting hazardous materials must carry a flash code. This diamond-shaped symbol is prominently displayed on both sides of the tank car and it tells you exactly what the contents are as well as the main danger such as whether it is flammable, corrosive, nuclear waste or more.  

There are four digits on the hazard flash code and you can find the exact material by referring to the Emergency Response Guidebook (DOT ERG). There is also a symbol (such as a flammable sign) and digits such as 3 which will help you find more information. 

Construction Information

The tank car also carries information about its construction. This can be helpful in the case of an accident as it tells responders, the type of steel used in manufacture. 

The DOT specification is always positioned on the right side of the tank towards the rear. This tells you the type of tank car it is and the pressure that it is under. This is marked by PRD (pressure relief device) and for example, if it is marked at 75PSI, the valve will open up if pressure builds above this, and close when normal pressure has been attained. 

The front of a tank car is known as the “A End” and the back end of the tank car is known as the “B End”. There is a brake on the bend but otherwise, the ends are identical. The capacity is also marked on the rear of the tank car with amounts provided in gallons and in liters as the trucks often cross the border into Mexico. 

A valve is usually situated beneath the tank so that it can be unloaded. This is protected by a skid plate so that if there is an accident or derailment the valve will not be sheered off, releasing its cargo into the environment. 


Bare Skinned or Jacketed? 

Some tank cars have a protective layer – known as a jacket. Others don’t and are known as bare-skinned. You can tell the difference by seeing if there is a saddle well that is visible on the side of the truck. If you can see this, it means that the tank car is bare-skinned so if there is any damage to the exterior of the tank, it could compromise the contents. If there is protective flashing over this area it means that the tank car is jacketed and any external damage may be restricted to the outside protective layer. 


Types of Rail Tank Car

There are two main types of rail car used for bulk liquid carrying. These are the 111 tank car and the 117 tank car and both types are categorized as general service trucks. 

The 117 tank car is stronger and offers greater protection. The DOT requires that all flammable liquids are transported by a 117 Tank car. A 117 tank car is required to be jacketed, is manufactured from thicker steel, and is fitted with thermal protection. 

A 111 general service tank car does not necessarily have to be jacketed, although some are, and this rail truck is not as robust as a 117 but is still often used in the transportation of some hazardous materials. 

DOT regulations require that all information is present on the shipping papers. However, if you can’t see this information and there is an incident you should call CHEMTREC on 800 -424 -9300. The number is manned 24/7 and is for any type of chemical emergency including spill, leak fire, exposure, or accident. 


The top of the tank car

There is a protective railing around the equipment on the top of the railcar. Within this framework, there are two valves protected by a raised steel cauldron-shaped cover. Once you have opened the cover you will see them.  The liquid valve is larger and this enables the tank car to be filled and in some cases emptied. The smaller valve is the vapor valve. 

There is also a man way. This circular hatch is securely sealed airtight and when opened provides the only access into the tank. If you open it, you will see straight into the tank and the material inside. If it is necessary to enter the tank this is the only route in. 

The pressure relief device is also on the top of the tank car. This automatically releases pressure if it rises above the level indicated by the PRD (marked on the side) and automatically closes once this has been achieved. 


What to do in the case of an emergency

If you are on the scene of a rail tank car emergency, the first thing to remember is that all the information regarding the hazardous cargo and the tank car construction is provided for you. Much of this information is provided on the tank car itself and you can also contact other agencies such as CHEMTREC for more assistance, so you are not alone. 

If there is an emergency, it is crucially important to take time to formulate a plan based on all the information provided, rather than acting fast and potentially causing greater risk to responders and the environment.