Few planes can operate on water, and the Boeing 737 is not one of them. Three 737 fuselages fell into a Montana river last week after the train carrying them derailed.

The train had left Wichita, Kansas and was en route to the Boeing assembly facility in Renton, Washington. According to Reuters, the 90-car train derailed about 18 miles from Superior, Montana, by the Clark Fork River on Thursday. Nineteen of the cars came off the tracks and three of the 737 fuselages fell into the river. The train, operated by BNSF Railway Co., was carrying six 737 fuselages, as well as parts for 747 and 777 airliners.

A spokeswoman for Montana Rail Link said the derailment's cause wasn't known but speed was not considered a factor, since that section of the track has a speed limit of 35 mph. She added that the line had been reopened by Saturday afternoon and no injuries had been reported.

"Our team of experts is assessing the damage," said Boeing spokesman Doug Alder in a statement, according to Reuters. "Once we determine the extent of damage, we will assess what, if any, impact there will be to production."

According to the Wall Street Journal, parts for the 737 as well as other Boeing models are made by Spirit AeroSystems, based in Wichita, Kansas. The Journal argues that the accident could delay Boeing production of the 737, as four fuselages were lost in the accident. The fourth did not land in the river but was torn up and was found near the train tracks.

Boeing has not released a statement announcing a delay in production, but Aviation Week said the company is ready for production delays. The accident will slow the company's current production pace of 42 737s per month. Spirit makes fuselages for the 737, as well as the nose section, wing center section and body panels for the 747-8. Many of these parts travel by train on the same line where the train derailed, the Journal reported.