DUPONT, Wash. — More than two weeks after an Amtrak train derailed in Washington state, killing three people and injuring dozens, federal investigators say they are still waiting to interview the engineer and another crewmember in the locomotive.

The National Transportation Safety Board said in a preliminary report Thursday that investigators haven’t yet talked to the 55-year-old engineer and a 48-year-old conductor training in the cab because of their injuries. The engineer has been with Amtrak since 2004 and an engineer since 2013.

The panel says damage from the Dec. 18 crash south of Tacoma is estimated at more than $40 million.

The train was recorded at 78 mph as it rounded a curve and derailed from a highway overpass near DuPont, Washington, spilling cars onto Interstate 5 below.

A 30-mph speed sign was posted 2 miles before the curve on the engineer’s side of the track and a similar sign was posted at the start of the curve.