 The 797F comes equipped with a new, more powerful and more efficient Cat C175-20 engine and an increased payload capacity of up to .The Caterpillar 797 series trucks employ mechanical drive powertrains in contrast to the diesel-electric powertrains of similar haul trucks offered by competitors.During initial development in 1997, a diesel-electric powertrain was considered for the 797, but this powertrain configuration was not developed because Caterpillar considered a mechanical drive powertrain more appropriate for market conditions at that time.