The government has instructed West Japan Railway Co. to investigate why a driver of one of its bullet trains that hit and killed a man who had entered the tracks did not report hearing an abnormal sound at the time, Transport and Tourism Minister Keiichi Ishii said Friday.

“I have ordered JR West to study why the driver did not make a report and whether or not that was an appropriate decision,” Ishii said.

A Nozomi train bound for Tokyo hit a man, identified as a 52-year-old caregiver from Fukuoka Prefecture, between Hakata and Kokura stations at around 2 p.m. Thursday. An unoccupied car was found on a road near the elevated railway track, to which a ladder and staircase were attached for access by maintenance workers.

After the train hit the man, a crack was discovered on the train’s bonnet. None of the roughly 200 passengers on board were injured.

At a news conference held Friday in the city of Osaka, JR West Vice President Yoshihisa Hirano apologized for the incident, adding that it had occurred inside a tunnel in Kitakyushu, about 17 kilometers away from Kokura Station.

According to the operator of the Sanyo Shinkansen Line, company rules require drivers to inform an operation center if they hear abnormal sounds. The driver said he did hear a sound but did not report it, reaching that decision based on a past experience aboard a train that had hit a small animal.

Last December JR West was criticized after a crack and oil leak were discovered on the undercarriage of a shinkansen train, in what is regarded as Japan’s most serious shinkansen incident.

Following that incident, JR West established a new policy that drivers must stop the train immediately when hearing strange sounds and are unable to confirm safety.