We study the structure of solutions of a discrete-time control system with a compact metric space of states X which arises in economic dynamics. This control system is described by a bounded upper semicontinuous function v:X×X→R1 which determines an optimality criterion and by a nonempty closed set Ω⊂X×X which determines a class of admissible trajectories (programs). We are interested in turnpike properties of the approximate solutions which are independent of the length of the interval, for all sufficiently large intervals.