The article presents a review of such engineering machines as bridgelayers. The paper analyses their operating methods and design process formalization. The authors use the existing bridgelayers as an example, with the aim of developing new software for automating and optimizing the design processes for their structural elements. The authors develop an algorithm for designing bridgelayer structural elements, determine the maximum permissible weight and length of the bridge. According to the described algorithm, the paper develops a mathematical model of the design process for the bridgelayer structural elements, implementing the algorithm in the form of a program for calculating the bridgelayer structural elements. Because of the execution and subsequent implementation of the program, developers will have a reliable and effective tool that improves the quality and reduces the time required to perform calculations in the projects being performed. Unification in terms of typical operations and structural details will reduce the cost of manufacturing bridgelayers. The aim of the study is to formalize the design processes for bridgelayers based on the results of analyzing bridgelayer designs and their operating principles. The task is to automate the design of the bridgelayer structural elements. The authors use such research methods as analysing and synthesising mathematical models of products. The novelty of the work lies in constructing a mathematical model of a bridgelayer, as well as in developing an algorithm and implementing its computer simulation. The results of the study are an algorithm and a mathematical model of a bridgelayer.