Performance evaluation of rail-mounted quasi-distributed optical fiber sensors for monitoring track transitions

Regular inspections of railroad tracks help ensure safe and cost-effective operating conditions. Inspection of track transitions is especially critical as these locations are subjected to high loads that can result in rapid deterioration. Optical Fiber Sensors (OFSs) represent one of the latest technologies for long-term, continuous structural health monitoring in harsh environments like railroad tracks. This paper presents findings from an ongoing research study evaluating the suitability of OFSs for monitoring and real-time condition assessment of track transitions. This paper reports on the laboratory and numerical modeling performance of the Fiber Bragg Grating (FBG) type of OFS. Data collected using FBG sensors are compared with those from conventional sensors such as strain gauges and Linear Variable Differential Transformers (LVDTs). The results confirm that rail mounted FBG sensors can accurately measure strain values under different levels of loading. Rail deflections calculated from these strain values match well with deflections measured using LVDTs.