The Economic Time Polymers
This article describes a case study wherein a short stretch of railway track formation coming under the jurisdiction of Northeast Frontier Railway, which was experiencing a severe problem of ballast sinking was stabilized using an indigenously manufactured knitted and coated polyester geogrid and a nonwoven geotexile. The observed field conditions are described in brief and the probable causes for unsatisfactory performance are listed. The proposed solution comprised of removing the ballast, preparation of the formation, laying of a nonwoven geotextile with a thin sand cushion at bottom and top and installing a knitted and PVC coated biaxial geogrid over this. The cleaned ballast was placed and packed over the geogrid. The installation procedure is explained briefly. The work was completed in August 2006 and the subsequent performance of the rehabilitated portion is found to be satisfactory as recorded by the department through issue of a performance report.
