The derailment of a freight train that occurred in Morimachi, Hokkaido last week has brought to light the hidden dangers that are close to us. This is a railroad crossing of the Dounan Isaribi Railway in Hokuto City, Hokkaido, on the morning of the 21st. Reporter Tadashi Fujita: "Employees of the Dounan Isaribi Railway are using a machine called a flaw detector to check for abnormalities in the tracks that cannot be seen with the naked eye." This is an emergency "rail inspection" that was ordered by the government following the derailment of a freight train that occurred in Morimachi last week. Fortunately, no abnormalities were found. Last week on the 16th, a freight train derailed on the JR Hakodate Line. A lump of iron was found at the derailment site. Corroded and crumbling. A piece of rail that had fallen apart. Reporter Tadashi Fujita: "The railroad crossing where the derailment occurred is on the way down the road that runs from the mountain side to the sea." Freight trains and express trains were running on these rails until just before the accident. Railway engineering expert: "The corrosion (of the rails) had progressed to this extent, and they had left it unattended. That's the most shocking thing." JR Hokkaido President Yasuyuki Watanuki: "We had absolutely no idea about the corrosion (of the rails' undersides). We must reflect on this." The derailment exposed another danger, and today we'll take another look. The accident occurred in Mori Town, southwestern Hokkaido, between Mori Station and Ishikura Station on the JR Hakodate Line, which runs along Funka Bay. The derailment is believed to have occurred at the Washinoki Road Crossing. Reporter Tadashi Fujita: "There is a big hole in the middle, and you can see that the treads and other things are scattered everywhere. If you follow the rails, they're gone, they're missing." A lump of iron was found at the derailment site. It's a corroded, tattered, and broken rail. This is a cross-section of a rail. From the top, they are called the "head," "underside," and "bottom." The "underside" is normally 15 mm thick, but the rail at the accident site was only 3 mm thick at its thinnest point. Reporter Fujita Tadashi: "As you can see, there is a sea and a port near the crossing, so salt damage from sea breezes may also be a cause of corrosion." Professor Tsunashima Hitoshi of Nihon University, who specializes in railway engineering, points out the possibility of salt damage as the cause of the rail corrosion. Professor Tsunashima Hitoshi of Nihon University (Railway Engineering): "The cause of the erosion (which accelerated the corrosion) is clearly salt damage. When salt adheres to the rail, rust occurs, and this causes the corrosion to progress rapidly." The rails at the crossing at the site were installed in 1992, more than 30 years ago. In September of this year, an inspection was conducted with an "ultrasonic flaw detector," and the echo image was found to be distorted. However, according to company rules, the rails were only visually inspected from above, and the rails were not inspected in detail by removing the floor plates. JR Hokkaido Managing Director Akio Shimamura: "We have been conducting inspections that focus on scratches inside the rail and corrosion at the bottom of the rail, but we did not foresee that corrosion at the bottom of the rail would occur first, which would lead to rail damage." Nihon University (Railway Engineering) Professor Hitoshi Tsunashima: "Naturally, salt damage is expected in areas like this that run along the coast. It doesn't seem like it could be foreseen. Of course, it should have been foreseen. It's not like JR Hokkaido has only recently been hit by salt damage. Have such past knowledge and experience been passed down sufficiently? That's the question..." In fact, JR East Niigata Branch published a paper on salt damage to rails. This was 12 years ago, in 2012. Tsunashima Hitoshi, specially appointed professor at Nihon University (Railway Engineering), said, "According to that paper, it is said that 4mm of (rail) corrosion progresses every 10 years, so the rails at the crossing where the accident occurred had been in use for 30 years, and simple math would suggest that it would not be unusual for there to be more than 12mm of corrosion, which matches up quite well with the amount of corrosion this time." JR Hokkaido manages 1,371 crossings in Hokkaido. Of these, based on the results of inspections with rail flaw detectors, it has been determined that approximately 220 crossings are subject to reinspection. He indicated that he plans to check the inspection data and, if necessary, remove the underlayment for further inspection. JR Hokkaido President Yasuyuki Watanuki: "For crossings on the sea side where heavy freight cars run, we will actually re-inspect them with a flaw detector." Nihon University (Railway Engineering) Professor Hitoshi Tsunashima: "I don't think that this means that JR Hokkaido's maintenance management system is completely flawed, but there were still gaps. I think we need to pool our ideas (including other companies) to find a way to inspect with as little manpower and cost as possible." Updated Thursday, November 21, 2024 at 20:33 #Hokkaido #News #HBC ◆Please subscribe to the HBC News channel. https://www.youtube.com/channel/UCCTp