OSAKA -- Three bullet trains on the Sanyo Shinkansen Line were delayed for up to 10 minutes Monday after drainage pumps in an undersea tunnel on the line in Kitakyushu were found to have temporarily malfunctioned, West Japan Railway Co. said.
An alarm sounded at 11:35 a.m. indicating that water levels had risen abnormally high inside the Shin-Kanmon Tunnel under the Kanmon Strait.
Upon inspection, JR West found that six automatic drainage pumps within the tunnel were not operating.
As a result, the water level, which is usually 8 meters below the bullet train tracks, was 4 meters higher than normal.
The Shin-Osaka-bound Kodama No. 634 bullet train from Hakata was halted at Kokura Station in Kitakyushu following the incident. It resumed operation at 11:45 a.m. after the railway company judged that the higher-than-normal water level did not pose any danger.
The company said that the pumps started functioning normally after they were manually restarted, adding that the cause of the malfunction is being investigated.
Several tons of seawater and groundwater leak every minute into the Shin-Kanmon Tunnel, which connects Shin-Shimonoseki Station in Yamaguchi Prefecture with Kokura Station, according to JR West.
The tunnel was completed in 1975.
Besides the Kodama No. 634, two other bullet trains were delayed by the incident, affecting some 600 passengers, the company said.