MISSOULA, Mont. -

A train derailment west of Missoula near Alberton caused Boeing fuselages to spill off the rail cars transporting them, and into the Clark Fork River below. Boeing will not tell us what will happen to the fuselages next, but NBC Montana spoke with a former retrofit engineer for insight.

Bill Lambrecht says a black line on the fuselage in the forefront of the image captured by rafters suggests severe damage. Lambecht explains another main concern will be scratches.  He says Boeing will inspect the surface with an electrical current that will reveal how deep any scratches possibly go.  

Since fresh water flows in the river and since the interior likely isn't installed, Lambrecht's opinion is that water damage is not as big a problem.  If it were salt water, that would damage the aluminum material.

He tells NBC Montana any fuselages with a large crease, as captured in rafter's video, will likely need to be scrapped.

"The one that was in the foreground, facing uphill...You could see a black line, kind of in the crown of the aircraft.  That looks to me like it's major damage.  It means the fuselage stringers are buckled, the skin itself has been crumpled,"  Lambrecht explains.

Lambecht estimates one fuselage can cost upward of $20 million.