Delivers precise, ultra-slow speed control for realistic operation. Programmable momentum simulates the drag of a heavy train or a light engine movement. Programmable starting and top-end voltage maximize performance. Open the throttle, and an impulse circuit delivers a burst of power at the right moment for smooth, jerk-free starts. Sets top-end voltage for exact speed control at every position on the throttle. Best of all you get the same performance from every engine.