A dynamic intermodal multiproduct freight network simulation-assignment model is presented with application to a large-scale intermodal rail network. Methodology pertaining to the simulation-assignment framework and representation and implementation considerations in dealing with large networks are discussed. The model is applied to a pan-European rail network spanning 11 countries from Scandinavia to Greece. Shipper decisions are disaggregated to an individual shipment level using a dynamic microassignment methodology in which a joint mode, path, service, and carrier choice is made. A mode choice function for this joint choice is calibrated, and issues relating to heterogeneity of freight characteristics are discussed. The model is validated by analyzing convergence patterns and measures of performance, namely, mode splits, compared with other studies. Two examples demonstrate the role of the model as a policy and decision support tool. The impact of expedited operations at international borders and infrastructure improvements on rail services is quantified.