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Safety

Tougher Tank Cars

Shippers say federal plan to boost safety of hazmat rail transport needs more work

by Glenn Hess
June 23, 2008 | A version of this story appeared in Volume 86, Issue 25

Stronger Design
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Credit: Union Tank Car Co.
The current fleet of rail tank cars used to transport toxic chemicals would have to be replaced with models better able to withstand side impacts and head-on collisions.
Credit: Union Tank Car Co.
The current fleet of rail tank cars used to transport toxic chemicals would have to be replaced with models better able to withstand side impacts and head-on collisions.

CHEMICAL SHIPPERS are urging the federal government to rethink its plan to improve the safety of railroad tank cars that carry the most dangerous hazardous materials, including two chemicals blamed for more than a dozen deaths in freight train accidents since 2002.

At a series of public meetings in Washington, D.C., last month, representatives of companies that make and ship chlorine, anhydrous ammonia, and other highly toxic chemicals told a panel of Department of Transportation (DOT) officials that many of their proposals include unrealistic timelines and may require technologies that currently do not exist.

"To achieve their objective, the proposed new rules must be based on sound technical data, balance the economic interests of both shippers and carriers, and not create incentives for shippers to transport more hazardous chemicals by highway since rail is by far the safest and most environmentally friendly method of land transport," said Karl Alexy, DuPont's corporate fleet engineer.

At issue is a package of proposed regulations jointly published in the Federal Register on April 1 by DOT's Federal Railroad Administration (FRA) and Pipeline & Hazardous Materials Safety Administration that seek to "drastically improve the accident survivability of railroad tank cars" that haul cargo classified as poison inhalation hazards (PIHs), which are commodities that pose grave threats to human health.

Industry officials stressed that the rail transportation of highly hazardous chemicals has been safe historically. "With over 1.5 million loaded moves of chlorine by rail since 1965, there have been only 10 tank car breaches," said Frank Reiner, vice president of transportation and emergency preparedness at the Chlorine Institute, a 220-member trade association of chlor-alkali producers, packagers, distributors, users, and suppliers. "Current chlorine rail tank cars have survived the overwhelming majority of accidents to which cars of this design have been subjected," he said.

But Reiner added that a series of recent incidents demonstrate that rail carriers need to make operational changes to reduce or eliminate derailments and collisions of trains hauling toxic chemicals. "At the same time," he acknowledged, "shippers and regulators must take action to improve accident survivability of railcars transporting PIH material."

The proposed changes follow on the heels of several deadly train accidents in which one or more tank cars were breached and either chlorine or anhydrous ammonia was released. In 2002, a Canadian Pacific Railway train derailed near Minot, N.D. Five tank cars ruptured, allowing 147,000 gal of anhydrous ammonia to escape. One person died and 11 were seriously injured. The collision of two trains near Macdona, Texas, in 2004 caused a release of liquefied chlorine from one train's tank cars. Three people died and more than 40 others were transported to area hospitals for treatment.

Then, in 2005, two Norfolk Southern Railway trains crashed in the small town of Graniteville, S.C., releasing an estimated 11,500 gal of chlorine. With nine fatalities and 240 injuries, it was the deadliest train wreck involving hazardous material in nearly three decades. After investigating the accident, the National Safety Transportation Board concluded that today's rail tank car is highly vulnerable to punctures and leaks in a derailment. "Even the strongest tank cars in service can be punctured in accidents involving trains operating at moderate speeds," according to the board's report.

The upgrades proposed by DOT would require the replacement of the entire U.S. fleet of tank cars used to transport PIH materials, estimated at 15,300, within eight years after the rule is finalized. Chemical shippers, who typically own or lease their fleets, would pay an estimated $125,000 for each of the new cars, a 47% increase over the cost of the standard tank car used to transport toxic chemicals today. The government projects the price tag for the industry would be approximately $350 million over a 30-year period—the economic life of a typical tank car.

The performance-based standards call for the new cars to be five times stronger than tank cars currently in service. They would have to be equipped with enough puncture-resistant protection to prevent penetration at speeds of 25 mph for side impacts and 30 mph for head-on collisions—more than double the puncture-resistance speeds for existing tank cars. The proposal says the standards could be met with any mix of innovative designs, improved materials, and new technologies, in combination with slower speeds.

"It is expected that the outer tank car shell and both head ends will be strengthened, the inner tank holding the hazmat cargo will be better shielded, and the space between the two will be designed with more energy absorption and protection capabilities," according to the proposed rule. The proposal permits an increase in the gross weight of tank cars from 263,000 to 286,000 lb to accommodate the likely heavier weight of an enhanced car.

THE RULE ALSO establishes a maximum speed of 50 mph for any train transporting a PIH tank car, a limit the railroad industry voluntarily adopted two years ago for trains with five or more cars carrying highly toxic chemicals. In addition, a temporary speed restriction of 30 mph is being proposed for all PIH tank cars that don't meet the puncture-resistance standard and are traveling through nonsignaled "dark territory," where there are no sensors and no communication network to relay the condition of tracks and signals to approaching train crews. About 40% of the U.S. rail network is dark.

Finally, the proposed rule requires that some of the oldest tank cars now in use be phased out on an accelerated schedule so they no longer carry PIH materials. This addresses the concern that tank cars manufactured prior to 1989 were fabricated from "nonnormalized" steel, which is more brittle and susceptible to cracking.

"When the opportunity to make major advances in safety is within our reach, we should not settle for incremental measures," FRA Administrator Joseph H. Boardman declared in announcing the proposed changes on March 31. "This is a major improvement. This is the right thing to do." DOT is expected to revise the plan to address many of the concerns that have been raised before a final regulation is issued. Boardman has said he hopes to have the new rule in place before the Bush Administration leaves office in January 2009.

In commenting on the proposal, shippers were split over the wisdom of imposing a 30-mph speed limit. According to DOT, there has never been a major release of chlorine in an incident where the car was moving at less than 30 mph. "The first line of defense in preventing the release of a PIH material in a rail incident is to prevent the incident from occurring," Reiner noted. "The fact that chlorine railcar releases have not occurred in highly populated areas is not a coincidence.

"It reflects that trains moving through such areas are normally operated at slower speeds than they are in less densely populated areas," he remarked. "The proposed operational requirements in dark territory would almost certainly result in an immediate and dramatic reduction in risk of release."

Jennifer Gibson, vice president of government and public affairs at the National Association of Chemical Distributors, said there is no guarantee that the 30-mph speed limit would increase safety. But she warned that the slower speed would increase security risks. The proposal is contrary to the important objective of having these materials in transit for as short a time period as possible, Gibson asserted.

"It would be much easier for a terrorist to track and target a train moving at 30 mph than to track one moving at 50 or 60 mph. At a time when stringent new regulations to increase security at fixed chemical facilities are being implemented, it would be particularly risky to increase the security exposure of PIH materials on the rails," she said.

Shippers agreed, however, that before a final rule is issued, DOT must take steps to ensure that rail tank car designs are available to meet the safety performance goals of the proposed standard. And to prove that a rail tank car design meets the new performance requirements, they said, it must first be validated by testing both the individual components and the full tank car.

"The normal process would be to build a number of prototype cars and put them in service for some time period to monitor performance," Reiner explained. "A service trial is necessary to assure that the new design performs well in service and that no unexpected detrimental consequences occur. This rule should not proceed until a design that complies with the rule has been tested and verified."

Guffain
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Credit: Fertilizer Institute
Credit: Fertilizer Institute

FRA has estimated that it will take two years to design and begin construction of tank cars that meet the new performance standard. In the remaining six years of the implementation period, the proposal requires steady replacement of existing tank cars with those meeting the enhanced tank head and shell performance standard. Half of each tank car owner's fleet would have to comply with the enhanced performance standards five years into the implementation period.

Reiner
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Credit: Glenn Hess/C&EN
Credit: Glenn Hess/C&EN

Shippers called that schedule unrealistic. "We are very concerned about the two-year timeline for design development and manufacture ramp-up outlined in the proposed rule," said Pamela D. Guffain, vice president of member services for the Fertilizer Institute, whose membership includes 14 companies that ship ammonia to customers for agricultural production and industrial applications.

"THE PRECISE TIME needed for design development, testing, prototype build, service trial, and then manufacturing is currently unknown, but every indication suggests that two years is very inadequate," Guffain said. "This is a matter of public safety. It would be imprudent to rush a new design into service without an adequate service trial period."

Guffain also expressed concern that all the research to date has focused on chlorine cars. "While we realize there are similarities between cars to be used for the transportation of chlorine and cars to be used for the transportation of ammonia, the two types of cars are not and will not be the same," she observed. "Very little has been done to develop the ammonia concept car. With this in mind, the timeline currently outlined in the proposed rulemaking is even more unrealistic." Several speakers said it could take as long as five to 10 years until a proven tank car design is ready for full-scale manufacture.

DuPont's Alexy pointed out that multiple designs will be needed because of the "unique and disparate chemical and physical properties" of PIH commodities. He noted, for example, that rail cars for oleum and sulfur trioxide must include adequate insulation to prevent the chemicals from freezing in transit, whereas cars used to transport chlorosulfonic acid must be constructed of stainless steel to prevent coloring of the acid.

Another set of design factors must be taken into account for anhydrous hydrochloric acid, Alexy said, explaining that the chemical requires a specialized container capable of being cooled to –20 ºF prior to loading and must include six to 10 inches of polyurethane foam for insulation. "These concerns are not insurmountable. They do, however, require careful consideration and demand significant design efforts and validation of puncture resistance," the DuPont engineer stated.

Thomas E. Schick, senior director of distribution at the American Chemistry Council, said a great deal of tank car safety research has been carried out during the past several years by DOT, shippers, and tank car builders. For example, in 2006, Dow Chemical joined with Union Pacific Railroad and Union Tank Car to launch the "next generation" tank car project, "which has already contributed significantly to knowledge about equipment performance and design," Schick said. He and others in the shipping community are concerned, however, about "whether or not the design concepts and performance standards that are contemplated in this rulemaking will actually be achievable."

Schick and other shipping representatives maintained that the performance criteria for the tank car head and possibly the shell as specified in DOT's proposal cannot be met with designs currently available or under review. Although the 25-mph standard for side impacts "may be feasible," Schick said, the 30-mph standard for head impacts "is not within the range of solutions that have been considered to date."

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Guffain also pointed to potential problems with the use of 286,000-lb tank cars, saying some customers' rail lines would not be able to handle the increased weight. "One ammonia shipper reports that the railroad track out of its facility is not 286 capable," she told the panel. "This facility is responsible for more than 50% of their ammonia shipments."

Where track is not capable of handling heavier cars, Guffain said, the only alternatives will be to switch to trucks, if possible, or "light load" tank cars. "Light-loading 286 cars to 263,000 lb will require shippers to increase their fleet size and number of shipments by 10% to service those weight-restricted locations," she said. "In either case, putting more trucks on the highways or more cars on the rail lines is clearly counter to the intent of the rule and will degrade, rather than enhance, public safety."

At the last of the four public meetings on May 29, industry officials said they would petition DOT to provide a solution for shippers who need to purchase new cars now. An interim standard for rail tank car safety, they said, would allow them to add tank cars with enhanced safety features to their fleets over next few years without facing the prospect of having to replace those cars once the DOT rule is implemented.

DOT should either define an "interim car that can be acquired to meet transportation needs until the cars envisioned in this rule are available to the market or provide for a grandfathering schedule," Reiner explained. "There is a need for the department to take a lead in providing an interim solution in order to assure uninterrupted availability of tank cars for PIH service."

Otherwise, he said, shippers could be forced to scrap new rail tank cars, which normally have a 25- to 30-year service life, after just eight years. "The lack of an interim solution has the potential to cripple some shippers and damage our nation's economy," Reiner warned.

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