The Japan Transport Safety Board on Wednesday opened a probe into an Osaka train's emergency stop as it crossed a nearly century-old bridge over a typhoon-swollen river on Sunday.

Two passengers on the Nankai Electric Railway Co. train were injured. Because Typhoon Lan was approaching the area, the Onosato River was swollen at the time of the incident. The tracks on one of the six bridge piers was found to be twisted, and it has been suggested that the pier may not have been strong enough to withstand the high water levels.

The sudden stop occurred on the bridge between Tarui and Ozaki stations. Train operations remain suspended.

The Osaka-based firm said Wednesday that it has not made repairs on the bridge in at least the past decade.

The company said it carries out safety inspections on the 94-meter-long and 3-meter-wide bridge every two years. No problems were found in the latest inspection, which was conducted in June.

"We decided as a result of our regular inspections that there was no need to repair the bridge," a company spokesman said.

The firm has not identified the cause of the accident but will take measures to prevent a recurrence, taking into account "all possibilities," the spokesman said.

The bridge, using steel girders and brick piers, was built in 1918. The Onosato River runs along the border between the Osaka Prefecture cities of Sennan and Hannan.