A major part of the narrow gauge line from Suwon to Inchon ran through Ansan and surrounding area. This area was until 25 years ago country side: none of the buildings in these pictures existed at the time! Even by the end of the existence of the line, in 1995, most of this area was still country side, although most of line 4 had already been built.
This series of pictures is the line in Ansan from a point between approx. Handaeap Station (한대앞역) and the (future) Sari Station (사리역) under the Yongsingoga Road (용신고가차도) all the way to a point to the west of Gojan Station (고잔역). On the map below (copyright: Naver, this is the location of the map) this is the route of the line 4 (the light blue line) between the two red lines, starting at 1 and walking towards 5. The grey line at 6 is the old narrow gauge line running towards Suwon (the top left of the map is towards Inchon, the bottom right is the Suwon side), but during 2013 and 2014 the new commuter line is under construction here, so nothing can be found there any more.