The National Transportation Safety Board says Conrail inspected the bridge the day before Friday's train derailment.

NTSB Chairman Deborah Hersman at Monday's press conference (WPVI TV)

NTSB Chairman Deborah Hersman at a Monday press conference said Conrail records indicate 9 work orders for problems ranging from debris on the bridge and light bulb replacement to reports about problems with the  bridge's locking mechanism.

On Wednesday, November 21 and again on Thursday, November 29--the day before the derailment--Conrail created work orders in response to complaints the locking mechanism was four inches from being completely locked. Hersman says the problem was repaired on November 29 and four trains crossed the bridge, the last one at 11:15PM but sent an automated message that bridge did not close properly.

NTSB Chairman Deborah Hersman and USCG Captain Kathleen Moore in Paulsboro (NTSB)

The next train derailed at 7:00AM the next morning.

Hersman says investigators, while eager to get to the accident scene, are deferring to the US Coast Guard's decisions regarding air safety.

Hersman also stressed that "nothing has been ruled out" in the NTSB's investigation especially since her team has not been able to get to the derailment scene.

SCHOOL STAYS CLOSED

The Coast Guard says schools in Paulsboro will stay closed until the tanker cars containing chemicals are removed from Mantua Creek. These schools include: Tracy Day Care, Head Start, Guardian Angels, Billingsport Early Childhood Center, Paulsboro High School, and  Loudenslager.

Paulsboro Court will also be closed until further notice.