Serial production of the International S13 integrated powertrain began Oct. 18 at the Huntsville, Ala., production facility operated by parent company Navistar, the company announced.The powertrain — comprising the S13 engine, proprietary T14 automated transmission and a dual-stage aftertreatment system — is the final internal combustion engine platform Navistar plans to develop as its German parent company, Traton Group, gears up for a future where it will only produce zero-emission vehicles, it said.Navistar completed a 110,000-square-foot expansion of the Huntsville plant in early October to support production of the S13 powertrain components. Work began in February 2020.The expansion boosts the facility’s footprint to 410,000 square feet, and the factory now has two assembly lines rather than one. The T14 transmission and the S13 engine each have an assembly line. In addition, there are three machining lines.