Abstract: A slide rail for mounting on a frame member of a tractor for supporting a fifth wheel assembly movably thereon. The slide rail includes a vertical attachment leg configured for securing the slide rail to a vertically extending wall of the frame member and a horizontal first leg joined directly to and extending from the attachment leg. A channel member having a slide channel is integrated with the first leg and configured to being positioned above a horizontal top wall of the frame member when the attachment leg is secured to the vertically extending wall of the frame rail. A rack containing a plurality of teeth may be included on the channel member. A pair of slide rails may be mounted to the frame members of a tractor and a pair of stop assemblies may be adjustably movably mounted across the ends of the slide rails.