This thesis introduces and validates a model of the operations at intermodal terminals suitable to be implemented with the MATLAB SimEvent discrete-event simulation tool. Using this approach, it is possible to model and calibrate a number of parameters which actually condition the operation of a real intermodal terminal; the resulting simulation produces several outputs useful to understand the behaviour of existing or designed terminals. After presenting already existing simulation approaches for intermodal terminals, the Thesis describes the general assumptions made within the current model, then presents the way in which the single sub-processes of the whole terminal operations are modelled within the MATLAB SimEvent tool.