This is a locomotive controller with a 230 volt / 18 VA switched mode power pack. It has four-step speed control for slow acceleration and powerful increases in speed up to the maximum speed. The controller has a single-knob operation for setting the track voltage and for setting the direction of travel by turning the control knob from the center setting. Locomotive controller dimensions: 130 mm / 5-1/8 (L) x 70 mm / 2-3/4 (W) x 50 mm / 2 (H).