Purpose: To determine the influence of geometric parameters on the most common elastic rod clip used in modern intermediate rail fastenings — the B-shaped clip (such as reinforced concrete rail (RCR) clip and anchor rail fastening (ARF)) — on changes in its stress-strain state. To propose a further direction of improving the design of elastic rod clips of rail fasteners to increase the reliability of the structure. Methods: The article presents the results of multivariate modeling of the geometric parameters of the clips (RCR — 20 pcs., ARF — 13 pcs.) with the analysis of their stress-strain state, using the methods of software and computer systems SolidWorks and Ansys Workbench. Results: Analysis of the design of modern fasteners has shown that the intervals for varying the geometric parameters of the clips (rod diameter, vertical radius, horizontal radius) have small limits and significant limitations associated with the requirements for ensuring the strength, elasticity and operability of the entire fastening. The necessity of considering options with vertical radii less than 60 mm has been revealed, which entails the need for a radical change in the shape of the clips themselves. Practical significance: As a result of the analysis of the calculations of multivariant models, the degrees of influence of the intervals of variation of the geometric parameters of rod clips (rod diameter, vertical radius, horizontal radius) on the stress-strain state have been determined. It is established that in order to further increase the elasticity of the clips, it is necessary to develop a new type of rail fastening with a fundamentally different shape (different from the modern B-shaped) elastic clip that does not have modern design limitations in geometric parameters.