This monograph examines methods and solutions to the pressing scientific problem of assessing the technical condition of transport infrastructure facilities in operation (reinforced concrete and metal bridges and overpasses, reinforced concrete culverts, railway tracks) by determining deformations in load-bearing elements and converting them into stresses. A monitoring system based on a strain gauge hardware and software complex (TMCC) is applied. Using TMCC, a diagnostic survey of more than 40 transport infrastructure facilities on the railways of the Republic of Kazakhstan has been conducted.The monograph presents the results of static and dynamic tests of bridge structures, overpasses, culverts, and railway tracks under various vibration excitation sources caused by transport loads (railway train, single locomotive, railcar, electric locomotives, and diesel locomotives). Based on the conducted field tests, an analysis of the stress-strain state (SSS) of transport infrastructure facilities has been carried out.