Roll-n-Go's Model 4200 Rail System is for boats weight up to 4200 lbs. This is a ready-to-assemble marine railway system constructed of marine grade aluminum. The track is 4" high structural "c" channel. It comes with 4 - 8' 11" track sections (just under 36 ft.) Read our section on how to determine your track length. The track is 42.3" wide. The sections connect easily with specially formed brackete and the bottom end has a stop to prevent the carriage from rolling too far.