Railway bridges are subjected to significant dynamic effects due to the passage of trains at high speeds (>250 km/h), which can induce resonance. Additionally, the presence of eccentric moving loads, skewed supports, and variations in cross-sectional geometry induces torsion in the bridges, coupled with bending. To understand the influence of all these effects on the Spanish railway bridges, here three common cross-sections are analyzed: slab on I-beams, slab on U-beams and single cell box girders, all designed for double track with a width of 14 m. The analysis of bending and torsion coupling is carried out by comparing 3D finite element models with semi-analytical models. The semi-analytical models are developed in the in-house software Caldintav [1]. On the other hand, the finite element 3D models are implemented in commercial software [2]. An important part of the analysis is to determine the torsional constant J for each section. In the case of box girder and slab on U-beams, the Bredt’s equation is used, and in the case of slab on I-beams the J is calibrated with a finite element model. As a conclusion, it is specified that a correct definition of J is critical to have accurately results when considering semi-analytical models, especially when bending is coupled with torsion.