Abstract: Based on the vehicletrack coupled dynamics, the vehicletrack coupled model for the roadrail fire fighting vehicle moving on the track was established and was compared with the traditional railway vehicle model. For the validation of the two models, field experiments were made. The comparisons between the experimental test results and numeral simulation results indicate that the vehicletrack coupled model is better in accordance with the reality than the traditional railway vehicle model. Based on the vehicletrack model, the unified objective function method was used for the optimization of suspension parameters. The optimization results indicate that rootmeansquare values of car body acceleration, dynamic travel of secondary suspension and wheelrail force are reduced by 626%, 542% and 681%, respectively. Consequently, the riding quality is significantly improved, the dynamic travel of secondary suspension is greatly shortened, and the influence of wheelrail dynamic interactions on the damage and deform of track structures is remarkably decreased.  

Key words: road-rail fire fighting vehicle, vehicle-track coupled dynamics, track irregularity, parameter optimization