A dual post receptor (30) of a safety rail system (10) has horizontal cross sections of an elongated shape with a width generally equal to and for slideable receipt of vertical posts (18) of conventional railings (12) and a length larger than double the diameters of the vertical posts (18). Elongated horizontal slots (38) are located in sides (34a, 34b) of the receptor (30) for receiving locking pins (22) also inserted through holes (20) in the vertical posts (18). Mounting the receptor (30) can be accomplished in a variety of manners including secured to a planar, horizontal mounting plate (46) secured to the bottom edges of the enclosure, secured to a vertical mounting plate (50) having a horizontal securement plate (56), secured to a protrusion (64) for slideable receipt in sockets such as in a truck bed, secured to a C-shaped clamp system of a variety of constructions, or the like.