Bulk Sr₂PdO₃ was synthesized by a modified solid state reaction and a detailed characterization was carried out using both microscopic and macroscopic experimental techniques. Pd site exhibits an electric field gradient of 5.9(1) ⋅ 10¹⁷ V/cm² due to the anisotropic local atomic configuration. A Curie - paramagnetic susceptibility indicating antiferromagnetic interactions superimposed to a core diamagnetic state is confirmed. A linear volume thermal expansion with a coefficient of 3.0(1) ⋅ 10⁻⁵ K⁻¹ at room temperature is extracted. A collection of Einstein oscillators, with an Einstein temperature of about 115 K, is involved in the thermal transport. Large atomic displacements were observed in Sr vibrations. No Pd or Sr valence change is observed up to 900 K. A moderate anharmonicity is identified and quantified in a macroscopic Grüneisen parameter of 2.5(1) at room temperature. The electrical resistivity reveals a semiconducting behaviour. A systematic reduction in electrical resistivity and a change in the conduction mechanism is observed upon thermal cycling which indicates that a peculiar electronic mechanism is involved.

Thermal dilation is a vital component of deformation along the extensive railway network infrastructure. To monitor subtle deformation, the synthetic aperture radar interferometry (InSAR) technique has been adopted as a space-borne geodetic tool. However, InSAR applications in railway stability surveillance have been largely limited by the sparseness of detectable point-like targets (PTs). Moreover, only one-dimensional linear displacements in radar line-of-sight direction can be measured by a single data stack. To address these issues, we developed an improved persistent scatterers InSAR approach that can retrieve thermal dilation effects with an increased number of PTs along the railways. This proposed strategy effectively combines SAR amplitude, interferometric phase, and the spatial information of railway structures to maximize the number of PTs. A least square fitting of the residual phase obtained by iterative spatial-temporal filtering with respect to temperature difference is used to estimate the thermal dilation of metal and concrete-asphalt materials. To validate the effectiveness of this approach, case studies using ENVISAT ASAR (ASAR) and TerraSAR-X (TSX) datasets were carried out on the railways of Beijing–Tianjin, Beijing–Shanghai, and Shanghai–Hangzhou. Subsidence velocity, gradient, and thermal dilation were used to identify hazardous grades along each railway. Furthermore, linear deformation rates in two dimensions, i.e., vertical and west-east directions, along Shanghai–Hangzhou Railway were inverted from ascending ASAR and descending TSX observations to reveal track conditions at a high level of detail.