Jacking apparatus having a fast repositioning stroke

A jacking apparatus for effecting movement of a load in a direction along a member which has a plurality of anchor points spaced apart in said direction, the jacking apparatus comprising a group of at least two double-acting hydraulic cylinders including at least one first cylinder and at least one second cylinder arranged in tandem, an hydraulic fluid supply means to provide hydraulic fluid pressure at a predetermined flow rate to said group of hydraulic cylinders, a piston in each of said cylinders, the first cylinder piston has a first side and a second side, a piston rod portion connected to one of said pistons for transmitting force between said pistons and a load, another piston rod portion extending between said pistons, said second side of said first cylinder piston is free of attachment of any piston rod portion, means for routing hydraulic fluid to respective first sides of said pistons to apply hydraulic fluid pressure to said pistons in a first direction, means for routing substantially all of said predetermined flow rate of hydraulic fluid to said second side of said piston of said first cylinder to apply hydraulic fluid pressure to said first cylinder piston in a second direction, means for routing hydraulic fluid from said first side to said second side of said first cylinder piston while hydraulic fluid pressure is being applied to said first cylinder piston in said second direction, and at least one anchor point engagement means to engage an anchor point in the member for movement of a load when hydraulic fluid pressure is applied to said pistons in said first direction and to disengage an anchor point in the member for movement of said cylinders when hydraulic fluid pressure is applied to said first cylinder piston in said second direction.