This is "Integration," where all six major sections of a 737 are fused together into a full fuselage. At Spirit Aerosystems, the spot from which this photo was taken is known as the "scenic overlook."

Last month, a train carrying 737 fuselages to Boeing in the Seattle area derailed in Montana, causing three of the fuselages to end up in a river. But normally, the trains make it to Washington safely, looking just like this.

Spirit technicians work on 737 entry and galley panels.

Large 737 sections are being worked on inside what are known as "trim and drill," where many of the holes and windows are drilled and cut out of the fuselage.

At Spirit Aerosystems in Wichita, technicians work on several 737 forward sections, which include the cockpit area.

A look at the underside of the unfinished entry and galley panels.

Two 737 cockpit sections sit on the floor at Spirit Aerosystems in Wichita, Kan.

Spirit employs a system of "master and slave" robots, in which one on the inside, like the one seen here, works in tandem with another one on the outside, each tracking the other as they drill holes and add small components.

A 737 side section, which includes a number of windows, sits on a trailer, awaiting further work by Spirit Aerosystems technicians.

A 737 fuselage, minus its nose, at the Integration position, where all the plane's major sections are fastened together, at the Spirit Aerosystems facility in Wichita, Kan.

A look into the interior of a 737 cockpit.

The interior of a 737 fuselage, at the Integration position. Once Spirit's work on the fuselage is complete, it's shipped by train to Boeing in Washington state, where the rest of the airplane is put together in the aviation giant's final assembly facility.

The empty cockpit section of a Boeing 737.

A Spirit Aerosystems technician works in the floor of the passenger section of a Boeing 737.

A major 737 section is lifted across the facility by a ceiling-mounted crane.

A look up at the underside of the 737 section being lifted by crane.

This tail section is one of six major sections that, together, make up the 737 fuselage.

A look at two 737 fuselages in Integration, at Spirit Aerosystems in Wichita, Kan.

A panel of windows that will be added to a fuselage sits on the floor at Spirit Aerosystems.

Two complete 737 fuselages sit outside the Spirit Aerosystems facility in Wichita, Kan., ready to be shipped to Boeing in Washington state.