The Air Transport Association, which represents major airlines, echoed the concerns and questions raised by Secretary Pena during today's hearing.

"Secretary Pena felt that they needed to do a sitewide standdown, that safety had to be looked at across the site."

Last month, Secretary Pena dismissed the nonprofit corporation that had managed the lab.

Secretary Pena said in an interview this week that he was concerned about overseas discrimination against American carriers.

Secretary Pena has indicated he will make such a decision early next year.

Secretary Pena noted that the United States spends nearly $1 trillion a year on transporation - 17 percent of the gross domestic product.

"There are no problems or questions about maintenance records or problems," Secretary Pena said.

Mr. Archer noted, as did Secretary Pena, that at least one locomotive had "literally flown through the air."

"We will improve aviation safety, because a corporate structure will allow us to bring on new technology much more quickly than in the past," Secretary Pena said.

Secretary Pena named Dr. Marburger, 56, as the lab's new director.