Improving the availability and reliability of a fleet of mobile cyber–physical systems as well as the ability to adapt themaintenance planning decisions when facing unexpected events at the fleet level is a major stake faced by the manufacturersand the operators. In the context of this study, the authors propose a reactive multi-agent system model for the fleetmaintenance planning of mobile cyber–physical systems. For that purpose, the ANEMONA multi-agent design methodology isused. In this methodology, the agents are modelled and then their organisational and interaction views are described. Numericalexperiments are carried out in static and dynamic contexts. In a static context, the proposed multi-agent system is comparedwith a mathematical programming model to validate the effectiveness of the former in satisfying the fleet's availability andreliability expectations. In a dynamic context, simulated perturbations are used to illustrate the reactivity of the proposed multi-agent system. Lastly, an application to rail transport for the maintenance of a fleet of trains at Bombardier Transportation Franceis proposed. For that purpose, the proposed multi-agent system is integrated in the model layer of a decision support systemnamed ‘MainFleet’ which is currently under development