Boeing is ensuring its plane parts get through Montana to its plants near Seattle after the train derailment and bridge collapse near Reed Point.
Truck drivers brought the fuselages about six miles on Interstate 90 to Reed Point beginning on Friday.
Crane operators lifted fuselages and rail cars off the trucks and lowered them back onto wheels on the tracks.
"The method of transferring these materials from rail to truck and then back to rail was identified as a safe, efficient option based on the location of the service disruption," said Andy Garland, Montana Rail Link director of communications.
The parts are destined for factories in the Puget Sound region of Washington state.
"Production and deliveries continue and we don't expect that this issue will change our full-year guidance," Jim Proulx, Boeing spokesman, said in a written statement.
Proulx says Boeing sells about 300 737's every year.
Montana Rail Link says this is its biggest project to help its customers impacted by the derailment.
"We're looking for alternative transportation solutions or maybe alternative transportation routes for some of our online customers," said Joe Racicot, Montana Rail Link president. "But this is the first kind of major operation specific to one customer."
Boeing has several of these deliveries every month and will continue the alternate route until the bridge is repaired.
