id	keyword
ap-5511	crossing
ap-5511	features
ap-5511	condition
ap-5511	monitoring
ap-5511	figure
ap-5511	spectral
ap-5511	track
ap-5511	lifetime
ap-5511	analysis
ap-5511	railway
ap-5511	acceleration
ap-5511	measurement
ap-5511	indicator
ap-5511	frequency
ap-5511	wavelet