An analysis of the transient configurations taken by a bundle of steps is presented. Growth from vapour is considered and only the interactions between steps mediated by surface kinetics are supposed to occur. It is shown that, at given supersaturation, the transient configurations are determined by the initial configuration and by the conditions prevailing at the two ends of the bundle, the dislocation and the border. The two latter conditions are essentially different in that the distance between steps is imposed by the frequency of their production at the dislocation while the rate is imposed to the step at the border of a growth hillock. As a consequence, we expect rates of steps depending also on the environment of every growth hillock. (c) 2006 Elsevier B.V. All rights reserved.