In this study, a computer model based on discrete-event simulation is developed to replicate the maintenance operations of a bus garage. Data relative to vehicle interarrival times and various maintenance services were collected, which were modelled using probability distributions. The system behaviour is studied under a different set of conditions aiming at supporting decision-makers on projects that intend to increase operational efficiency to meet demand requirements. Alternative scenarios are tested, which include: incrementing the number of mechanical pits to evaluate variations on the system's performance, and reallocating resources to increase operational efficiency. The results show that either incrementing or reallocating the number of mechanical pits can generate significant gains in relation to the lead-time of vehicles as well as benefits concerning to resource utilisation.s