This paper proposes a novel robust adaptive speed/position tracking control for a linear induction motor (LIM) with both end-effect and secondary resistance unknown. The practical current-fed controlled LIM, with residual current error, is considered, i.e., the traditional ideal current-loop assumption is relaxed. More practical conditions, such as bounded primary voltage and a finite absolute-integral of current tracking error is considered. To overcome the high nonlinearity and nonzero current error, a backstepping method, combining virtual desired variable synthesis, is developed for the speed and position tracking. Then, the controller achieves asymptotic speed and position tracking even With unknown parameters and immeasurable secondary flux. Furthermore, the effect of the residual current error is attenuated in an L(2)-gain sense. The experiments for several scenarios are carried out to verify the theoretical result.