Hydraulic Drive Train for a Frac Pump

A hydraulic drive system is employed to transfer energy generated by a diesel engine to a frac pump. The hydraulic drive system includes a gearbox comprising a plurality of gears being coupled to and driven to produce rotational movement by the diesel engine, at least one hydraulic pump coupled to at least one gear of the gearbox, and operable to, driven by the rotational movement of the at least one gear of the gearbox, force a fluid at high pressure into at least one high-pressure fluid conduit, and at least one hydraulic motor coupled to the at least one high-pressure fluid conduit to receive the high-pressure fluid, and operable to transform energy in the high-pressure fluid to a rotational movement, which is used to power and drive a plurality of plungers in the frac pump.