Shinkansen makes emergency stop when cars uncouple on route to Tokyo 19/9/2024

[Gostav]

Kyodo News https://english.kyodonews.net/news/...eastern-japan-stops-after-cars-disengage.html

A shinkansen made an emergency stop between northeastern Japan and Tokyo on Thursday after its two linked trains uncoupled, railway operator JR East said, but no injuries were reported among the some 320 people aboard.

The incident involving the Komachi and Hayabusa high-speed trains on the Tohoku Shinkansen Line marked the first time they have uncoupled while in motion, according to JR East. The trouble occurred at 8:10 a.m. between Furukawa and Sendai stations in Miyagi Prefecture.

A total of 72 trains on the Tohoku, Yamagata, and Akita Shinkansen lines were canceled and 35 delayed, affecting approximately 45,000 passengers, JR East said.


"It's not uncommon for Shinkansen trains to stop for safety checks, but I was surprised because this was the first time I had heard that they disconnected," a 59-year-old man who was on the train told Kyodo News in a phone interview.

There were no derailments of the cars.

JR East temporarily halted all bullet train services between Tokyo and Shin-Aomori in Aomori Prefecture for inspection. It resumed operations around 1:10 p.m. after completing inspections of both the Hayabusa and Komachi trains at the site and moving them to Sendai station.

The cause of the incident is being investigated but no external abnormalities have been found on the coupler, according to JR East.

The trains were connected at Morioka station and were heading to Tokyo at a speed of 315 kilometers per hour when they detached. The Komachi was around 300 meters away from the Hayabusa after the emergency stop was made.

JR East is the only operator in Japan that couples trains with different compositions for a Shinkansen service, and the connecting and separating of the red Komachi and green Hayabusa trains at Morioka attracts many railway enthusiasts.

Combined photo taken from a Kyodo News helicopter on Sept. 19, 2024, shows the couplers of the Hayabusa No. 6 bullet train (L) and the Komachi No. 6 bullet train that disconnected while in motion on the Tohoku Shinkansen Line, forcing an emergency halt in Osaki, Miyagi Prefecture. (Kyodo)

Photo taken from a Kyodo News helicopter shows the Tohoku Shinkansen Line's Hayabusa-Komachi No. 6 bullet train bound for Tokyo -- the Hayabusa portion (top L) and the Komachi portion (bottom) -- decoupled and stopped on the tracks in Osaki, Miyagi Prefecture, between Furukawa and Sendai stations on Sept. 19, 2024. (Kyodo)

 

[Beebman]

Here's a 10-minute Japanese language TV news report (including some studio analysis of the incident) with a long description of the video's contents which I've run through Google Translate:

"At that time" the speed was 315km/h... Tohoku Shinkansen was separated while in motion. What was the possible cause? [News Station] (September 19, 2024)

The Tohoku Shinkansen, a major artery connecting the Tokyo metropolitan area and Tohoku, stopped for five hours on the 19th. The cause was a problem in which the coupled "Hayabusa" and "Komachi" suddenly became detached while traveling. "Komachi 6" from Akita was coupled with "Hayabusa 6" which departed from this station at Morioka Station. It departed at 7:37 a.m. The coupling came off and the train stopped 30 minutes later, about 6 kilometers from Furukawa Station. There were a total of 320 passengers on the two Shinkansen trains. "Hayabusa" started moving at around 11:30, three and a half hours after it stopped. "Komachi" also started moving shortly after. However, the impact is widespread. Service between Tokyo and Shin-Aomori was temporarily suspended. Not only the Tohoku and Akita Shinkansen, but also the Yamagata Shinkansen was suspended, affecting about 45,000 people. Up until now, there have been many incidents of couplers coming off on conventional trains. Most recently, in November last year, the Oigawa Railway in Shizuoka came off the coupling between the electric locomotive and the passenger car, causing an emergency stop. It has been recognized as a serious incident that could have led to an accident. However, this time, it was on Japan's fastest Shinkansen. According to JR East, this is the first time that a Shinkansen has come off while in motion. At the time, it was traveling at about 315 kilometers per hour. A passenger on the Hayabusa said, "There was nothing unusual at all, and the train stopped quietly. It was just the usual temporary stop and restart. After a while, the driver made an announcement, and I thought the coupling had come off or there was some kind of problem with the coupling." A passenger on the Komachi said, "(Q. There wasn't much of an impact. I wondered why it stopped. (Q. The speed dropped normally and then stopped.) Yes." This year, there have been a series of problems with the Shinkansen. In January, there was a power outage between Ueno and Omiya. Some sections were suspended for the entire day. It has been pointed out that the overhead wires that supply electricity to the trains may have fallen down and come into contact with the Shinkansen. There have also been accidents on the Tokaido Shinkansen where maintenance trains have collided with each other and derailed. Normally, the separation is done at the station. Why did it come off while the train was moving? JR East says that there was nothing abnormal with the appearance of the coupler and that the cause is under investigation. ◆The accident occurred when the "Komachi" train from Akita was coupled with the "Hayabusa" at Morioka Station and heading to Tokyo. The coupling part came off between Furukawa and Sendai on the way. "Hayabusa" and "Komachi" are physically connected, but they are also connected electrically. Each motor is running and both are running in a way that produces power. This separation occurred while the train was moving at 315 kilometers per hour. After the separation, each car ran nearly 5 kilometers and stopped. At that time, the two cars were about 300 meters apart. The coupling is done by inserting the protrusions on both sides into holes. According to JR East, there are no particular abnormalities at the moment, and they are investigating the cause. ◆We asked railway journalist Jun Umehara about possible causes. Umehara said, "It was a failure in the electrical system. Since the couplers are disconnected on a daily basis, they are designed to be disconnected by pressing a button. Normally, the button does not disconnect when traveling at a speed of 5 kilometers per hour or more. It is possible that an incorrect signal was sent due to an electrical system failure." According to JR East, "For safety reasons, when the coupler is disconnected, both cars are automatically braked almost simultaneously, and this mechanism was activated." In addition, to avoid collisions, the brakes on the rear cars are designed to be stronger than those on the front cars. The conductor of the Komachi was in the car next to the front car where the driver's seat is located, and when he sensed something was wrong, he quickly went to the front car and used the manual brakes. Umehara pointed out, "One wrong step could have led to a serious accident." "If there was a curve or a slope, the vehicle in front may have slowed down faster than the vehicle behind, which could have led to a collision, so a thorough investigation is needed," he said. [TV Asahi News] https://news.tv-asahi.co.jp

 

[185]

In fairness our Hokkaido Shinkansen was 40 late due to a track defect 15 miles north of the Seikan tunnel last week. No delay repay for us lol. But... how?! How does a modern coupler on a high speed train fail? Astonishing.

 

[GatwickDepress]

Oh dear, somebody's going to be having a meeting with no cha or daifuku.

From the title, I was imagining the intermediate carriages decoupled, so this is somewhat of a relief - still quite bad though.

 

[alf]

Can the units be manually uncoupled from the rear unit front driving cab when in motion?

 

[bahnause]

The event is not as unusual as you might think. Therefore, the units (or at least most of them) also have a detection system for uncommanded uncouplings and react accordingly. I don't know why it took them so long to reattach the two units, if the couplers were undamaged.

 

[nwales58]

As the two sets are portions which join or split at Morioka, northbound the Komachi set might have wanted to try being a slip coach.

 

[43096]

The event is not as unusual as you might think. Therefore, the units (or at least most of them) also have a detection system for uncommanded uncouplings and react accordingly.

I would hope that any train would have the protection of either a brake pipe or train wire running through the train that fails safe in a situation where the train divides i.e. it dumps the brake. It's only been a requirement in the UK for well over 100 years after the Board of Trade's "lock, block and brake" mantra was made law in the 1889 Regulation of the Railways Act.

 

[Tester]

As the two sets are portions which join or split at Morioka, northbound the Komachi set might have wanted to try being a slip coach.

To be boringly pedantic, it would be the Hayabusa doing the slipping!

 

[bahnause]

I would hope that any train would have the protection of either a brake pipe or train wire running through the train that fails safe in a situation where the train divides i.e. it dumps the brake. It's only been a requirement in the UK for well over 100 years after the Board of Trade's "lock, block and brake" mantra was made law in the 1889 Regulation of the Railways Act.

Modern systems have to cover a little more. They must clearly indicate that a train separation has taken place and that it is not another fault causing an emergency brake. This is because if the couplings are undamaged, it could otherwise be possible to reset one of the units without any problems, confirm the new train configuration by mistake and continue the journey. Of course, this is not possible with a mechanically damaged brake line of any sort.

 

[boiledbeans2]

I would hope that any train would have the protection of either a brake pipe or train wire running through the train that fails safe in a situation where the train divides i.e. it dumps the brake. It's only been a requirement in the UK for well over 100 years after the Board of Trade's "lock, block and brake" mantra was made law in the 1889 Regulation of the Railways Act.

What if the front train has stronger brakes, and slows down quicker than the rear train after separation?

 

[Gostav]

The event is not as unusual as you might think. Therefore, the units (or at least most of them) also have a detection system for uncommanded uncouplings and react accordingly. I don't know why it took them so long to reattach the two units, if the couplers were undamaged.

Uncoupling should only happen at speeds below 5 km/h, obviously shouldn't happen at high speeds like that.

 

[172007]

We had a class 150 class153 pair uncouple on the move (the 153 stopped with an automatic emergency brake application) and the 150 continued on to the next station.

The wiring on the coupler pins had got accidently muddled so when the Conductor pushed the PA button to make an announcement it actually sent an uncouple command (or at lease enough of a voltage pulse for it to happen).

These things with safeguards etc can come down to something very very simple.

 

[bahnause]

What if the front train has stronger brakes, and slows down quicker than the rear train after separation?

In this case, the two parts would not move apart after separation.

 

[D365]

We had a class 150 class153 pair uncouple on the move (the 153 stopped with an automatic emergency brake application) and the 150 continued on to the next station.

The wiring on the coupler pins had got accidently muddled so when the Conductor pushed the PA button to make an announcement it actually sent an uncouple command (or at lease enough of a voltage pulse for it to happen).

Did an NIR (National Incident Report) get raised?

 

[Nippy]

In the early days of the 165/166s we had an uncoupling at speed of an Empty Coaching Stock. The train left a track circuit showing occupied at Ealing Broadway. I stopped the front portion by signals between Acton and Old Oak Common and asked the driver if their train was complete. He looked back and said no, we have lost a unit somewhere. I can‘t recall how the incident was resolved.

 

[bahnause]

I have only experienced it once so far. A check of the couplers showed nothing unusual. After the usual reset of the two units and resetting the ‘train separation’ fault message, they could be coupled again. The onward journey was trouble-free.

 

[Beebman]

NHK's domestic news service has a report in Japanese today about a likely cause of the separation (I've run it through Google Translate):

https://www3.nhk.or.jp/news/html/20240926/k10014592531000.html

A foreign object measuring several millimeters was found in a device near the connecting part of the Tohoku Shinkansen This month, a Tohoku Shinkansen train car came loose while running in Miyagi Prefecture. When East Japan Railway Company (JR East) inspected the car, they found numerous foreign objects, several millimeters in size, thought to be made of metal, in a device near the coupling. JR believes that the foreign objects may have caused the coupling to come loose, and is continuing its investigation.
On the 19th of this month, between Furukawa Station and Sendai Station in Miyagi Prefecture, the Tohoku Shinkansen's Hayabusa and Komachi trains were traveling at a speed of approximately 315 km/h when their couplings came undone, automatically activating the brakes and bringing the train to an emergency stop.

This was the first time that a JR East Shinkansen train's couplings had come undone while in motion.

When JR East subsequently inspected the trains, they found numerous foreign objects, several millimeters in size, thought to be made of metal, behind a switch for an air passage pipe near the coupling on the Komachi side.

As a result, they are investigating further, believing that the couplings may have come undone due to the foreign objects.

JR East has previously explained that an inspection of both the Hayabusa and Komachi trains last month revealed no abnormalities in the couplings, and that the coupling work carried out at Morioka Station was normal.

 

[MarkyT]

NHK's domestic news service has a report in Japanese today about a likely cause of the separation (I've run it through Google Translate):

https://www3.nhk.or.jp/news/html/20240926/k10014592531000.html

Perhaps this metalic debris bridged a control contact that was supposed to be open which then supplied power to the actuator initiating uncoupling. So what is the debris? Swarf from some previous metalworking in the depot that wasn't cleaned up properly, or has is resulted from wear and tear in operation?

 

[172007]

Did an NIR (National Incident Report) get raised?

Have not got a clue. You would have to be in the correct department to answer that.