In a motor vehicle, the term powertrain or powerplant refers to the group of components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, drive shafts, differentials, and the final drive (drive wheels, continuous track as in tanks or Caterpillar tractors, propeller, etc.). Sometimes "powertrain" is used to refer to simply the engine and transmission, including the other components only if they are integral to the transmission. In a carriage or wagon, running gear designates the wheels and axles in distinction from the body.

A motor vehicle's driveline consists of the parts of the powertrain excluding the engine and transmission. It is the portion of a vehicle, after the transmission, that changes depending on whether a vehicle is front-wheel, rear-wheel, or four-wheel drive, or less-common six-wheel or eight-wheel drive.

In a wider sense, the power-train includes all of its components used to transform stored (chemical, solar, nuclear, kinetic, potential, etc.) energy into kinetic energy for propulsion purposes. This includes the utilization of multiple power sources and non–wheel-based vehicles.

Earl Richard Stewart, Jr. (October 15, 1921 – July 11, 1990) was an American professional golfer who played on the PGA Tour in the 1950s and 1960s; and was a college head golf coach in the 1970s and 1980s.

Stewart was born in Dallas, Texas. He attended Louisiana State University and was a member of the golf team. In 1941, he won the NCAA Championship, and led the Bayou Bengals to a share of the NCAA team title in 1942.

Stewart had three wins in PGA Tour events during his career. His first win came in 1953 at the Greater Greensboro Open. He would win the Ardmore Open later that year. His best finishes in major championships were T10 at the 1952 U.S. Open and T15 at The Masters in 1953. Like many professional golfers of his generation, Stewart earned his living primarily as a club pro. His third and final win on the PGA Tour, the 1961 Dallas Open Invitational, came on his own course at the Oak Cliff Country Club.

Stewart was the head golf coach at Southern Methodist University from 1975–1987. He coached both the men's and women's teams. Men's golf was dropped by the university in 1980. He won a national championship with the women's team in 1979. One of his students was future two-time U.S. Open and PGA Champion Payne Stewart (no relation). In 1987, he was inducted into the National Golf Coaches Association Coaches Hall of Fame for his role as a women's collegiate golf coach at SMU.