Vehicle modular rail system

A modular rail system for supporting one or more accessories on a pickup truck bed including a front wall, an end wall, and opposing first and second side walls, the side walls each having a generally horizontal top surface, the system comprising:

• a first elongated rail assembly including a first base rail capable of releasably connecting with said first side wall, a first fill rail positioned adjacent to and connected with said first base rail, and a first cap rail overlying said first base rail and said first fill rail and being connected to at least one of said first base rail and said first fill rail;
• a second elongated rail assembly including a second base rail capable of releasably connecting with said second side wall, a second fill rail positioned adjacent to and connected with said second base rail, and a second cap rail overlying said second base rail and said second fill rail and being connected to at least one of said second base rail and said second fill rail;
• flexible cover means having first and second sections positioned over at least a portion of said bed for covering said portion of said bed;
• first attachment means associated with said first and second cap rails and said first section of said cover means for lockingly attaching said first section of said cover means to said first and second cap rails;
• and
• hatch means pivotably connected at fixed points on said first and second elongated rail assemblies for supporting said second section of said flexible cover means and for providing easy access to said truck bed;
• said hatch means comprising a frame movable between an up position and a down position, locking means associated with said frame for locking said frame to said first and second rail assemblies when said frame is in said down position, and second attachment means for lockingly attaching said second section of said cover means to said frame;
• and
• said frame including an L-shaped member which overlaps said end wall when said end wall is in a closed position and said frame is in said down position to secure said end wall in said closed position.