A drive system provides a displacement mechanism for driving motion of a device using energy stored in an energy accumulator in a non-electric form. A charge/discharge arrangement selectively charges the energy accumulator with energy derived from an energy source while isolated from the displacement mechanism, and the connects the energy accumulator to the displacement mechanism to provide energy for driving motion of the device. The energy accumulator may be hydraulic, pneumatic or gravitational. Examples of devices driven by the system include elevators, escalators and vehicles.