Left panels: time variation of the EUV intensity perturbations in the rapidly propagating quasi-periodic wave trains, extracted from TD MAP 1 and 2 at a position of about 85 and 155 Mm (see Fig. 8). The perturbations are shown in arbitrary units. The red vertical dashed lines mark the start and peak of the flare. The blue vertical dashed line indicates the time of the sudden increase in the soft X-ray flux. The sequence of the propagating wave train fronts is seen as the increase in the amplitude of the intensity variation. Right panels: wavelet spectra of the signals.