REHABILITATION TECHNIQUES TO IMPROVE LONG-TERM PERFORMANCES OF HIGHWAY-RAILWAY AT-GRADE CROSSINGS

摘要

The primary purpose of the highway-railway at-grade crossing is to provide a smooth surface for the safe passage of rubber-tired vehicles across the railroad. The crossing support and surface in the jointly used area represent a significantly expensive unit cost of the highway and railway line. The ideal highway crossing will maintain a smooth surface and stable trackbed for a long period of time. This will reduce costly, frequent disruptions to highway and railway traffic (to adjust the track or renew the surface due to rideability concerns), while concurrently providing improved operating performance and long life. Technology is available for rapidly renewing highway crossings within one day using a panel system with specifically designed layered support and premium materials. The procedure involves complete removal of the old crossing panel and trackbed materials ~ and replacing them with an asphalt underlayment layer, a pre-compacted ballast layer, a new track panel, and a new crossing surface. A cooperative effort between the local highway agency and the railway company will reduce costs, improve the quality of the finished product, and reduce outage of the highway and railroad. A major objective is to minimize disruption to both highway and railway traffic during the renewal process in addition to extending the life of the crossing. Suggested procedures, based on experiences for several installations, are presented. Typical schedules are for the railroad to be to be out-of-service for a maximum of four hours and for the highway to be closed only eight to twelve hours. Results are presented for crossings instrumented with pressure cells to document Pressure levels within the layered portion of the crossing structure. In addition, long-term Settlement measurements and assessments for several crossings are documented. The measurements indicate significantly reduced long-term settlements of crossings incorporating the rapid-renewal, layered system, while maintaining acceptable smoothness levels. These long-term performance evaluations indicate this practice ensures long-life, economical, smooth crossings for improved safety and operating performances for both highway agencies and railway companies.