Development of a Scaled-Down Test Rig for Wheel–Rail Contact Thermal Experiments Using Optical Sensors

Rail–wheel contact measurement is crucial for several reasons. First and foremost, it directly affects the safety of passengers, crew, and the general public. Accurate measurements help identify irregularities in wheel–rail contact, such as wheel defects, wear, or track anomalies, which can lead to derailments or accidents if left unaddressed. An inventive technique for measuring the temperatures at rail–wheel contact at various speeds is presented in this research. The novel approach uses a 1:5 scaled-down test rig model of a wheel and rail with a fiber Bragg grating (FBG) sensor to combine the experimental and finite element analysis simulation to determine the rail–wheel contact temperature. By employing the various data acquisition and data analysis techniques, rail–wheel contact temperature at different speeds ranging between 10 kmph and 40 kmph was determined 1538.735–1538.831 nm with a center wavelength of 1538.438 nm. The results illustrate the possibilities of the downsized test rig with experimental observations at varying speeds by examining the benefits of FBG sensors over traditional sensors. The experimental results are used to determine the equivalent wavelength shift. FBG sensor design and simulation are done with the grating modulation depth (MOD) optical tool. For this temperature range and Bragg's wavelength of 1538.438 nm, the sensitivity of fiber Bragg grating is observed to be 13.6 pm/°C.