The article describes the process of developing a virtual model of a reduced-order cooling module for subsequent integration into a 1D virtual model of a diesel locomotive. A description of the steps in the model creation process is provided, including data collection, selection of mathematical models, and verification and validation procedures. The results of the work show that the created virtual model provides a convenient and accurate tool for analyzing and optimizing the cooling system of a diesel locomotive, which expands the possibilities for optimizing the design and improving the system control algorithms, which in turn leads to increased reliability and efficiency of its operation. The study highlights the prospects for the application of reduced-order virtual models in the railway industry. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/).