1. A system comprising: a coupler configured to be positioned between adjacent cars of a powered system that includes a train the coupler configured to be positioned in a slack state that includes one of a stretched slack state or a bunched slack state based upon separation of the adjacent cars; a controller configured to be positioned within the locomotive of the powered system and to determine a mismatch of a model of the slack state for the coupler of the powered system and actual behavior of the powered system on a real time basis from a plurality of input parameters including at least one of a locomotive parameter, a track parameter, a train parameter, or a train stability state; wherein the coupler is included in plural couplers of the powered system and the model is a lumped-mass model where the couplers positioned between the adjacent cars of the train are assumed permanently in one of the stretched slack state or the bunched slack state; wherein the train stability state being one of a stable state or an unstable state, the stable state representative of the couplers being in the stretched slack state or the bunched slack state, the unstable state representative of a first one of the couplers being in the bunched slack state and a second one of the couplers being in the stretched slack state; wherein the controller is configured to determine a jerk of the locomotive based on a time rate of change of acceleration of the locomotive, the acceleration based on a speed of the locomotive; and wherein the controller is configured to determine the mismatch of the lumped-mass model on the real-time basis based upon at least two of the jerk, a current notch of an engine of the locomotive, and the train stability state being modified by a respective threshold amount within a designated time period.