Heavy equipment company PT XYZ faced critical challenges in managing 18 trucks in June, leading to significant queues and an urgent need for effective handling. This study aims to determine the facility’s maximum capacity and optimize the loading and unloading process, reducing loading and unloading times and queues to minimize operational impacts. We analyzed the capacity and queuing time using the one-lane, one-phase queuing method, and Arena software. Manual calculations showed an average queue time of 1.8 h, with two trucks that could not be accommodated, for a total time of 21.5 h over three shifts. The arena simulation showed that 16 out of 18 trucks could be served efficiently, resulting in a queue time of 4.4 h. Improvement scenarios based on total cost analysis showed that Scenario 2 offered better performance and cost efficiency than Scenario 1. It can also be applied to other transportation companies facing similar challenges by improving logistics efficiency. PT XYZ contributes to industry practice by optimizing sustainable transportation processes and reducing environmental impacts, thus providing insights to maximize capacity and optimize loading and unloading processes. It offers a model for other transportation companies to improve their operations sustainably and efficiently.