LightRail 3.5 Extreme Duty Greenhouse Package Light Mover Grow Light System Comes with Versatile Connecting Strut Channel Compatible Rails: Greenhouses need supplemental plant light. That’s for the fall and winter months and to extend the day, year round. And, because we get a longer grow light run with sunlight present, this greenhouse package allows for up to 13’ of run for one LightRail 3.5 IntelliDrive Motor. Plus, we get much better yields. That’s because more leaf area is reached with better light. And, there is no blocking the natural greenhouse sunlight as with stationary grow light shadows. For details, see below.