By The Boeing Company

The new 737 North Line deepens Boeing’s connections across the Puget Sound.

Boeing’s $1 billion investment in Washington State underscores the company’s long-term commitment to the Puget Sound region, where the Renton factory has served as the home of the 737 — Boeing’s best-selling commercial airplane family — for more than five decades. Boeing will continue building 737s in Renton for years to come. As the latest generation, the 737 MAX continues to see robust global demand from airlines, with thousands of airplanes in the company’s backlog.

As part of its efforts to better meet this demand, Boeing recently opened a new production line for the narrow-body airplane. Known as the “737 North Line,” this fourth production line sits approximately 40 miles north of Renton, in Boeing’s Everett factory.

Since it opened in 1967, the Everett site has been synonymous with Boeing’s wide-body airplane programs — including the 747, 767 and 777. With the introduction of narrow-body production to the site, Boeing will increase its capacity by building on the long history of aerospace in the Puget Sound region.

Preparing for Production
The transition to a multi-site production strategy for the 737 has been a years-long undertaking. First, construction within the Everett factory transformed an existing wide-body production bay into one suitable for narrow-body production. This included building new tooling to hold 737 fuselages before landing gear are installed, as well as dividing the space into more factory positions to align with the production process used in Renton.

In addition, Boeing engineers developed a wing transportation system — allowing partially assembled airplane wings to travel from Renton to Everett by road. Teams in Renton will continue assembling the wing structure, before transporting the wing to Everett for the installation of hydraulics and electronic systems. Once finalized, the wing is ready-at-hand to be joined with the fuselage.

People in Focus
Alongside construction and tooling upgrades, Boeing invested in the development of the North Line team. By design, this team comprises both experienced mechanics from Boeing’s existing programs and newly hired teammates. This approach ensures that safety and quality standards remain the North Line’s top priority, along with strengthening ties between all four 737 production lines.

All North Line teammates, regardless of tenure, completed training in Renton. Newly hired mechanics completed the standard 12-week Foundational Training, followed by structured on-the-job training where they worked shoulder-to-shoulder with experienced mechanics. Teammates coming from other commercial airplane programs also completed training in Renton to learn the specifics of the 737 build process.

Slow and Steady
The 737 North Line began operation in early July, beginning with a phase of low-rate initial production. During this period, the build process is intentionally slowed to allow for quality and conformance checks and to make adjustment as needed.
Once conformity requirements are met, the North Line will be fully integrated into the 737 MAX production system. This integration will provide the essential capacity needed to support increased production rates in the future, further solidifying Boeing’s commitment to meeting the needs of its global customers.