I. Introduction
Iterative learning control is very suitable for devising the tracking controller of high-speed trains that run periodically on the same railway, e.g., the same tunnels, slopes, and bridges [1]–[9]. However, on account of the damping effect of wheel rails, couplers, and so on as well as the disturbance of external environments, the speed delay occurs frequently during the operation of train, thus attenuating the control performance of trains. Hence, this article proposes a novel iterative learning control approach for the high-speed trains with time-varying delay to track the given reference displacement and velocity.