Railcar Covers and Lids

One solution to fugitive coal dust emissions is to cover the train cars with a physical lid. As uncovered coal trains travel long distances, wind and vibration can release fine particulate matter into the air. A secure lid system could significantly reduce these emissions by containing the dust at its source. In many cases, including in Hampton Roads, operators choose to use alternative coal dust suppression methods, citing the cost of the new infrastructure that would be required.

Uncovered coal hoppers, parked at Pier 6 in Lambert's Point, owned and operated by Norfolk Southern. (SouthWings). 2023.

Use

Covered hopper cars, which are equipped with a roof, have historically been used for cargo like grain, sugar, and fertilizer that must be protected from exposure to the weather. Coal, which can be exposed with minimal effect to the product, has been transported in open hopper cars.

In an effort to prevent dangerous fugitive coal dust emissions, some railroads and coal shippers have begun putting covers on the coal as well. However, covering the coal remains a rare choice for dust control.

A 2004 experiment by Ferreira & Vaz found that the use of covers reduces the amount of dust released to be less than 20% of the quantity eroded from the uncovered wagon. In other words, when compared to the no-cover situation, the semi-cover reduced the dust amount released more than 80% for the full-load situation.

Limitations

Installing lids involves substantial retrofitting expenses and operational hurdles, as loading terminals and mines would need new infrastructure, and lids complicate fast unloading. Many operators instead favor chemical dust suppressants, which have been shown to achieve a high reduction in dust at lower cost.

Covering Coal in Hampton Roads

Railroads are not required to cover cars carrying coal as they travel through Virginia.

Norfolk Southern is required to submit annual reports on their fugitive coal dust emissions, and continues to monitor the issue. According to these reports, Norfolk Southern conducted engineering studies to determine the feasibility and cost effectiveness of covering the rotary dumpers at Lamberts Point. The studies concluded that it is impractical to enclose the structures due to the age and design of the rotary dumpers, along with the fire hazards presented by enclosing the equipment. The study also found that, because the average PM₁₀ readings have been and continue to be an order of magnitude below the EPA National Ambient Air Quality Standard, the benefits of enclosing the dumpers are far outweighed by the costs. Instead, the coal terminals and transporters commonly use sprinklers and wet suppression systems.

In 2011, Dominion Terminal claimed to have invested $5 million to improve chutes that transport coal along conveyor belts, limiting dust by limiting coal being dropped from significant heights when the coal is moving. At that time, about half of the chutes had been converted, and the rest planned to be finished within the next few years.

Documents

• Ferreira et al., Full-Scale Measurements for Evaluation of Coal Dust Release from Train Wagons with Two Different Shelter Covers, Journal of Wind Engineering and Industrial Aerodynamics, 91, 10, 1271–83, 2003
• Ferreira et al., Wind Tunnel Study of Coal Dust Release from Train Wagons, Journal of Wind Engineering and Industrial Aerodynamics, 92, 7–8, 565–77, 2004

• Covers for Rail Transport of Coal, June 2, 2016