HYDRAULIC POWERED OPTION   -   WORK-OVER RIG When driven by hydraulics, the winch can be operated in two useful modes. It can be used as a free-fall winch for drilling and bailing in the usual way, and after locking off the hoist brake, can be controlled by hydraulic valves for safe lifting - power up and power down. The second - safe lifting - mode allows controlled pulling of pumps and casing, and provides the ability to safely lift tools and enter them into casing. Change between modes is instant. The hydraulic version is useful as a work-over machine for handling well pumps while retaining the ability to surge and bail during well development and cleaning of screens. The action of a bailer used in conjunction with a free-fall winch is several times more effective than air lifting in development and cleaning wells, and is cheaper. Hydraulic operation can be with either integral engine driven system, or by separate independent power pack driven by a variety of power sources. These may be engine driven, electric motor driven or compressed air powered.