Rail: Mind the people

Rail transport plays a vital role in the movement of large volumes of goods across North America and, by and large, it is a very safe mode of doing so. But accidents do happen; often they take place in remote areas, posing little risk to people and property (though often with environmental impacts) but, when they take place among people, they can be devastating, as was demonstrated most clearly by the derailment of an oil train in the middle of Lac-Mégantic, Quebec in July 2013, when 47 people were killed.

In the wake of that disaster, authorities in both Canada and the US set about putting in regulatory changes that would either help prevent accidents or, at the very least, reduce the impact of such accidents by hastening the phase-out of older tank cars. Neither of those approaches has yet made a significant impact on the number of railroad accidents, however, as the record demonstrates.

Last year, a Norfolk Southern freight train derailed in the small Ohio town of East Palestine and, although its impact was innocuous compared to that in Lac-Mégantic, it may turn out that this is the event that forces regulators and industry to take serious steps towards improving the safety record.

FACTS OF THE CASE

The National Transportation Safety Board (NTSB) has now released the findings of its investigation into the East Palestine crash, which as always with railroad incidents sought to determine (a) the proximate cause of the derailment and (b) the behaviour of the wagons during and after the derailment. In this case, rather more unusually, NTSB also looked closely at the emergency response, to address concerns raised by nearby residents and lobby groups.

The incident itself was not particularly noteworthy: on 3 February 2023, a Norfolk Southern freight train was passing through the small Ohio town of East Palestine – almost mid-way between Cleveland and Pittsburgh – when 38 rail cars derailed. Eleven of those derailed cars were tank cars with hazardous materials and three of those tank cars were breached, leading to a fire. In response, a 1-mile (1.6-km) evacuation zone was established, affecting some 2,000 residents.

As is not uncommon, the proximate cause of the derailment was an overheating bearing on a hopper car, that caused an axle to separate. This had been spotted by a hot bearing detector and the train crew had already begun slowing the train when the derailment occurred. However, NTSB says the crew received a low-priority alert, which did not reflect the true condition of the failing bearing; furthermore, the spacing between detectors was such that the crew did not have adequate warning prior to the failure of the axle.

Research will be necessary to determine whether changes to wayside bearing defect detection systems – such as lower alert and alarm thresholds – would produce a significant safety improvement, NTSB says. Research is also necessary to determine what operational responses to bearing alerts and alarms are sufficient to prevent derailments.

NTSB says that the post-derailment fires most likely began after a DOT-111 tank car with some flammable hazardous material was punctured. These tank cars are gradually being phased out, as they have been identified as a weak link in the transport of hazardous (particularly flammable and toxic) material by rail following the Lac-Mégantic incident and other events in the US. There have been calls for the phase-out schedule to be accelerated but there are economic barriers to this and industry bodies representing shippers, especially in the US, have been vocal in opposing a more aggressive timescale. NTSB recognises these concerns but is adamant that the continued use of DOT-111 tank cars contributed to the fire and the severity of the hazardous materials release.

WHERE THE ARGUMENTS START

What made the East Palestine derailment more newsworthy was the decision to carry out a vent-and-burn response on five tank cars carrying vinyl chloride (VCM), shipped as UN 1086. These tank cars were not mechanically breached during the derailment but over the next day four were exposed to the growing fire and to material released through pressure relief devices. Norfolk Southern and its contractors informed the incident commander that a dangerous polymerisation reaction was occurring within a VCM tank car, following indications of a rise in temperature. This was seen as posing a risk of over-pressurisation and a boiling liquid expanding vapour explosion (BLEVE) and, after consultation with the US Environmental Protection Agency, a decision was taken to expand the evacuation zone and perform a vent-and-burn on all five VCM tank cars on the afternoon of 6 February.

Shaped charges were used to breach the tank cars, allowing VCM to flow into a trench where it was ignited by flares. This generated black clouds that contained, among other things, hydrogen chloride and phosgene. Although air quality readings showed no need for concern, residents in nearby counties reported a chemical smell and officials in one neighbouring area advised residents to shelter in place. While there was an increase in volatile organic compound and particulate matter recorded over the next two days, this was also said to be below the permissible threshold.

Nonetheless, the release of chemicals with potential long-term health impacts caused immense concern, which was amplified by press reports. There was also a widespread impact on wildlife, both in nearby waterways and among mammals, from product released as a result of the derailment and during the movement of derailed wagons.

Furthermore, it rapidly became apparent that the vent-and-burn approach was not necessary; indeed, NTSB notes that dissenting opinions were ignored and that Norfolk Southern’s insistence that the tanks were at risk of catastrophic failure was misplaced. NTSB also notes that the Chlorine Institute’s pamphlet 171, which was consulted in the response effort, includes erroneous information about polymerisation.

NTSB also says that, contributing to the exposure of emergency responders and the public to the post-derailment hazards, were Norfolk Southern’s delay in transmitting the train consist information to responders and the insufficient training received by Ohio’s volunteer firefighters.

CHANGES TO BE MADE

As a result of its investigation, NTSB has made several recommendations to various parties, including the Federal Railroad Administration (FRA), the Association of American Railroads (AAR), the Pipeline and Hazardous Materials Safety Administration (PHMSA), the Chlorine Institute and state and local authorities.

PHMSA has already responded, issuing its final rule under the real-time train consist rulemaking this past June (see page 24).

Regarding the decision to vent and burn the VCM cargo, NTSB recommends that the Chlorine Institute to review its pamphlet to ensure it is accurate and suited to supporting emergency responders. NTSB also urges the American Chemistry Council (ACC) and the Chlorine Institute to ensure their members are aware of the events at East Palestine and emphasise the importance of making their expertise available during an incident response. Norfolk Southern (and, by implication, other major railroads) should establish a policy of communicating all expert opinions to the incident command. FRA is asked to disseminate current and updated versions of its existing study on the vent and burn method to help guide incident commands in the future; and PHMSA is asked to spread awareness of FRA’s most current guidance by referencing it in the next edition of the Emergency Response Guidebook (ERG).

It is unlikely that this is the end of the story; there are several outstanding law suits and Norfolk Southern has promised to invest in the East Palestine community. Its case has not been made any easier by another derailment near Springfield, Ohio just a month after the East Palestine incident, though in this case there were no hazardous materials involved, and another derailment as a result of a collision of Norfolk Southern Trains in Easton, Pennsylvania on 2 March 2024.

source: https://hcblive.com/rail-mind-the-people/