id	keyword
ap-8344	tunnel
ap-8344	defects
ap-8344	figure
ap-8344	data
ap-8344	infrastructure
ap-8344	mapping
ap-8344	lining
ap-8344	mobile
ap-8344	maintenance
ap-8344	survey
ap-8344	images
ap-8344	inspection
ap-8344	railway
ap-8344	system
ap-8344	approach
ap-8344	management
ap-8344	sector