This presentation shows how the in-train forces experienced during car dumping can be reduced by altering the velocity-time profile of the positioner. During wagon indexation large coupler loads are experienced along the train. These large cyclic loads can cause: high fatigue rates on wagon connection components, in-service coupler failures resulting in split trains, high wagon maintenance and production delays. Analogue and numerical models created to simulate train unloading dynamics are shown in this presentation. These models allowed testing of various positioner velocity-time profiles for their effect on in-train coupler forces. Findings show a surprisingly strong relationship between positioner velocity and peak coupler forces leading to practical findings for the operation of car dumpers and rolling stock.