Imafuku Tunnel 5 is a short tunnel with a length of 45 meters, but is the only one out of the 12 pieces of the Imafukusen Line still currently in use. Inside the tunnel is a seismometer put in place by JR West. The seismometer is a way for JR West to measure earthquakes occuring in the San-in Region in order to safely operate the Sanyo Shinkansen.
Originally, Imafuku Tunnel 5 was planned to have 2 bridges built on either side so that it would be possible to cross the Shimokogawa River when going through the tunnel. Today, you can still see the bridge abutments and a pier in the river. Originally, there were two sets of piers, however, only one pier on each side remains as the other was lost due to flood damage.