Installing or repairing a railroad crossing on a busy street is time-consuming and thus a major concern for most transportation officials. Contractors must build up the recessed area between the rails and both sides to be even with the street elevation; however, recesses must be adjacent to the upper portion of each rail to accommodate the flanges on railcar wheels.
Wood or asphalt paving have typically filled the recessed area. Cast-in-place concrete and modular precast concrete crossing structures have been used also. Frequently, however, maintenance is needed. This type of railroad-crossing maintenance can be extremely expensive and labor-intensive.
Using precast concrete technology, a group of Oldcastle engineers has just patented a "Precast Reinforced Concrete Railway Crossing Slab." The invention is a slab that extends across the surface of conventional railway ties, with slots or gaps for railway rails. It includes a post-tensioning system in the form that provides reinforcement to the slab.
The precast railway-crossing slab can be used with or without surface or edge metal plating. Flange way fillers are optional. The slab may be formed integrally with grooves to receive the rails or as three separate slabs with screw holes for securing to railway ties.
The Oldcastle engineers chose as the preferred post-tensioning system for their railway crossing slab the Dywidag Monostrand Post-Tensioning System.
This precast slab system has substantial advantages over previously used methods: greater durability, greater resistance to cracking, less likelihood of damage during handling by forklifts, and it can be used without the metal edging or surface plating required by conventional slab-crossing systems.
Keywords: rail, Lego, Oldcastle, precast, post-tension, Dywidag, Monostrand