A method for controlling coupling between a first machine and a second machine, the first machine is a gas turbine and the second machine is a steam turbine, the first machine including a first rotating shaft (18, 202) having an associated first positional phase angle (PA 1) defined by a first shaft indicia (26, 210) and the second machine including a second rotating shaft (20, 204) having an associated second positional phase angle (PA 2) defined by a second shaft indicia (28, 212), the method comprising: monitoring a rotational speed (S 1) and rotational angle of the first shaft; controlling rotation of the second shaft comprising: bringing a rotational speed (S 2) of the second shaft to a predetermined rotational speed relative to the monitored rotational speed of the first shaft, wherein acceleration of the second shaft is controlled such that the second shaft indicia is within a predetermined angle (R PA) relative to the first shaft indicia upon the second shaft being brought to the predetermined rotational speed; and upon the second shaft being brought to the predetermined rotational speed, actuating a coupling to mechanically couple the first and second shafts such that the second shaft indicia is within the predetermined angle relative to the first shaft indicia, wherein, during the step of controlling rotation of the second shaft, the first shaft rotates at a substantially constant speed and the speed of the second shaft is increased, wherein said substantially constant speed of rotation of the first shaft is a normal operating speed of the first shaft, wherein said predetermined rotational speed is the normal operating speed of the first shaft, wherein as the speed of the second shaft approaches the speed of the first shaft the acceleration of the second shaft is reduced to substantially zero, wherein when the acceleration of the second shaft is substantially zero waiting until the second shaft indicia is within said predetermined angle relative to the first shaft indicia, wherein when the second shaft indicia is within said predetermined angle relative to the first shaft indicia accelerating the second shaft to the speed of the first shaft for said actuation of said coupling to mechanically couple the first and second shafts. monitoring a rotational speed (S 1) and rotational angle of the first shaft; controlling rotation of the second shaft comprising: bringing a rotational speed (S 2) of the second shaft to a predetermined rotational speed relative to the monitored rotational speed of the first shaft, wherein acceleration of the second shaft is controlled such that the second shaft indicia is within a predetermined angle (R PA) relative to the first shaft indicia upon the second shaft being brought to the predetermined rotational speed; and upon the second shaft being brought to the predetermined rotational speed, actuating a coupling to mechanically couple the first and second shafts such that the second shaft indicia is within the predetermined angle relative to the first shaft indicia, wherein, during the step of controlling rotation of the second shaft, the first shaft rotates at a substantially constant speed and the speed of the second shaft is increased, wherein said substantially constant speed of rotation of the first shaft is a normal operating speed of the first shaft, wherein said predetermined rotational speed is the normal operating speed of the first shaft, wherein as the speed of the second shaft approaches the speed of the first shaft the acceleration of the second shaft is reduced to substantially zero, wherein when the acceleration of the second shaft is substantially zero waiting until the second shaft indicia is within said predetermined angle relative to the first shaft indicia, wherein when the second shaft indicia is within said predetermined angle relative to the first shaft indicia accelerating the second shaft to the speed of the first shaft for said actuation of said coupling to mechanically couple the first and second shafts.