LightRail 4.0 AdjustaDrive KitLight Rail 4. 0 AdjustaDrive Kit: The Light Rail 4. 0 AdjustaDrive Kit has both a 0 to 60 second adjustable time delay for pausing the grow light at both ends of its travels, promoting even growth from end to end; but it also has a 2 to 4 feet (. 6 to 1. 2 meters) per minute adjustable speed control as the Motor goes along the Rail. This feature covers a wide range of grow light intensities and travel distances, and provides considerable flexibility.