grillwork for automotive uses , fencing , and railings includes a series of parallel extending rail members each attachable to cross support members at two locations thereon , to support each rail member and to hold each rail member in position on the cross support members . two mounting pieces , attachable to respective cross support members , are used to hold / mount each rail member . the mounting pieces each slide into locked position at an end of each rail and also provide an end cap / finish piece for the rail . the rails and the mounting pieces are manufactured of similar materials and by similar manufacturing techniques . the materials of manufacture can extend from various metals , to various thermoplastics , to reinforced plastic composites such as fiberglass reinforced materials .