First we would have to have exactly the same source and absorber isotope material in order for resonant scatter to happen. If this condition is satisfied we wouldn’t need any moving components.However if we would have different chemical environments,energy shift would be present. The first problem would be,that we can’t have infinitive track on which our fast train would ride, so that wouldn’t be a great solution. However, what we can do is move our source forward and backwards.
Second problem would be speed of sound, but since our isotopes would be the same,just the chemical environment would differ,thus the shift would be very small and our speed would have to be small as well.