SEATTLE, July 5 (Reuters) - A train derailment in Montana this week damaged a shipment of jetliner fuselages and other large parts on its way to Boeing Co factories in Washington state from Spirit Aerosystems, Boeing said on Saturday.
It was not yet known if the accident might affect production of planes, the company said.
Boeing said a BNSF Railway Co train loaded with six 737 narrowbody fuselages and assemblies for its 777 and 747 widebody jets derailed near Rivulet, Montana, on Thursday.
Nineteen cars on the westbound train derailed, Aviation Week reported, quoting BNSF. Three cars carrying 737 fuselages went down an embankment and into a river.
Boeing said it had experts at the scene "to begin a thorough assessment of the situation." The cause of the derailment was under investigation, it said.
Spirit Aerosystems, based in Wichita, Kansas, builds all of Boeing's 737 fuselages and Boeing currently produces 42 finished 737s a month, meaning it needs a steady supply of fuselages.
Boeing declined to comment on whether it would seek a second source for the fuselages, as some industry experts have suggested.
Spirit said it was working closely with Boeing following the incident.
"The Spirit team's resolve was tested with an even greater challenge as recently as the 2012 Wichita tornado. We are confident that, working together, we will overcome whatever challenges may be presented," the company said in a statement.
Officials at BNSF were not immediately available to comment.
The train also was carrying fuselage panels and a "lower lobe" for the 777, and a leading edge flight surface for the 747, Boeing said.
"Our team of experts is assessing the damage. We will know more once our experts have completed their inspection. Once we determine the extent of damage we will assess what, if any, impact there will be to production," Boeing spokesman Doug Alder said in a statement.
"We are working with our rail partners to determine timing and when the tracks will be cleared. However, alternate rail routes are available for future shipments." (Reporting by Alwyn Scott; Editing by Frances Kerry)