The agency says it will publish a preliminary report on the incident in two weeks, as it is still examining evidence from the train and cars.
NTSB investigators have identified and examined the rail car that initiated the derailment. Surveillance video from a residence showed what appears to be a wheel bearing in the final stage of overheat failure moments before the derailment. The wheelset from the suspected railcar has been collected as evidence for metallurgical examination. The suspected overheated wheel bearing has been collected and will be examined by engineers from the NTSB Materials Laboratory in Washington, D.C.
The tank cars are currently being decontaminated. Once the process is complete, NTSB investigators will return to Ohio to complete a thorough examination of the tank cars.
The vinyl chloride tank car top fittings, including the relief valves, were removed and secured in a locked intermodal container pending an NTSB examination. Once the fittings are examined by NTSB investigators, they will be shipped to Texas for testing, which will be conducted under the direction of the NTSB.
