Continuously Scanned Image (CSI) gives convenient image data for inspection of elongated facilities in railway, such as tracks, rolling stocks and so on. We have developed a system named ConSIS to take the CSI at a high data rate of 40M pixel/sec, which is composed of a line-sensor camera and a datarecorder. As the result of field tests taking the CSI of tracks, rolling stocks and tunnel walls, feasibility of an inspection system using the CSI was confirmed. Additionally, we have developed a prototype image database system to examine effective use of the CSI, in which some useful functions such as normalizing a scale of the CSI, scrolling the continuous image, zooming up a fine image for observation, are implemented. Further, we have developed a method to extract cracks on a concrete surface for automatic inspection using the CSI and a computer.