The Hokuriku Tunnel fire (北陸トンネル火災事故) was a train fire that broke out at about 1:09 a.m. on November 6, 1972, in the Hokuriku Tunnel (total length 13,870 m) on the Hokuriku Main Line between Tsuruga Station and Minami-Imajō Station in Tsuruga, Fukui Prefecture. The majority of passengers and crew members were killed or injured.
Overview of the accident
At around 1:09 a.m., a fire broke out beneath the smoking room seats in the dining car (Oshi 17 2018) of car 11 of the express train 501 "Kitaguni" (きたぐに), bound for Aomori from Osaka. The train was hauled by an EF70 electric locomotive and consisted of fifteen Series 10 passenger cars. The fire occurred as the train was entering the Hokuriku Tunnel.
Upon notification from passengers, the conductor applied the emergency brake and the driver made an emergency stop, so the train stopped immediately in accordance with operating regulations (at a point 5.3 km from the Tsuruga entrance). The crew began protective measures for the train (installing track circuit shunts on the opposite up line to set its signals to red) and then started firefighting with fire extinguishers and similar equipment. However, as the flames grew stronger and the crew judged that extinguishing the fire was impossible, they began the work of detaching the burning cars.
However, the work faced difficulties because of the intense flames and the narrow tunnel. At about 1:24 a.m., the front part of the burning car was detached and moved away. At about 1:29 a.m., rescue was requested from Imajō Station and Tsuruga Station, the stations at each end of the tunnel, and the work of detaching the front part of the burning car continued. However, at 1:52 a.m., a water-drainage guide container installed on the tunnel ceiling was burned by the heat and fell onto the overhead catenary wire, causing a power outage, and the train was left unable to move.
Progress
Because the accident occurred late at night, many passengers were asleep in the sleeper cars at the front of the train, and the smoke was severe, so evacuation and rescue were difficult. The train had stopped roughly in the middle of the tunnel, so it was too far for passengers to escape on foot, and there was no firefighting equipment other than fire extinguishers. Firefighting hoses could not be brought into the tunnel, so rescue had to proceed without firefighting. It was an accident in which entering to rescue and entering to fight the fire were both difficult. At the time, Japanese National Railways maintained that fires could not occur inside an electrified tunnel, so it had installed no smoke-exhaust or firefighting facilities at all. In addition, the tunnel lights had been switched off because the labor unions opposed them, arguing that they "interfere with operation." Although measures were taken after the accident was reported, such as rescue trains being dispatched from both ends of the tunnel, a combination of adverse conditions led to the outcome: the fire had broken out in the dining car, so its discovery and reporting were delayed, and the intense smoke and toxic gases from the burning car filled the tunnel, which had no ventilation system. As a result, 30 people (one of them the driver who was the instructor) died and 714 were injured. All deaths were determined to be due to carbon monoxide poisoning.
At the same time, the up line was being operated by the 506M express train "Tateyama 3" (Tateyama 3号, 475 series EMU). However, because of the red signal caused by the installation of the track circuit shunts, it stopped at Kinome signal station, about 2 km ahead of the accident site. Afterward, a track circuit shunt was displaced from the rails (it is presumed that an evacuee kicked it, although the cause was ultimately unidentified), and the signal turned green. The driver, though sensing something was wrong, started the train at slow speed. After advancing about 300 m, the train encountered passengers who had fled from "Kitaguni," so the doors were opened and 225 people were rescued. The train then reversed through the tunnel toward Imajō and escaped successfully.
A stroke of luck for "Tateyama 3" was that there was a neutral section between the accident site and the train. Because of this, power was not supplied in the section where "Kitaguni" was stopped, but power continued to be supplied at the position of "Tateyama 3," about 2 km away. Furthermore, regarding the power outage caused when the water-drainage guide container melted and fell onto the catenary, there was a theory that the subsequent heat had caused the wire to slip off the catenary again and the short circuit cleared, so if power had been restored when the deceased driver made contact, self-rescue would have been possible. However, because it was difficult to determine the cause of the power outage at the time of the accident, it was considered that the decision to abandon the restoration of power was unavoidable, given the possibility of secondary damage from re-energizing the line.
- 01:04 – "Kitaguni" departs Tsuruga Station two minutes late
- Around 01:14 – Fire confirmed and train stopped
- 01:23 – Up "Tateyama 3" passes Tsuruga Station
- Work to detach the cars begins
- 01:40 – "Tateyama 3" stops at Kinome signal station
- 01:41 – JNR disaster countermeasure headquarters established
- 01:50 – Tsuruga Mikata Fire Association notified
- 01:52 – High-speed circuit breaker at Tsuruga substation operates, stopping power supply to the section
- 02:00 – Fire engines arrive at the Tsuruga entrance; no JNR personnel present
- 02:01 – Kinome signal station clears to proceed; "Tateyama 3" departs at slow speed
- 02:03 – Driver of "Tateyama 3" discovers evacuated passengers and stops; doors opened for rescue
- 02:07 – Notification to the Nairetsu Fire Association (Imajō side)
- 02:30 – Permission to enter granted from the Tsuruga side for rescue motor cars
- 02:40 – "Tateyama 3" returns to Imajō Station
- 06:39 – Second rescue train enters
- 10:30 – Third rescue train arrives at Tsuruga Station
Cause
The cause of the fire was determined to be a short circuit in the electric heating device under the long seats in the smoking room of the Oshi 17 car (the wiring violated standards, and the old wiring was found to have deteriorated). In the early stage, there were speculations that the fire had started from a coal range in the Oshi 17 galley or from a cigarette in the smoking room, but these were not confirmed.
Countermeasures after the accident
Using this accident as a lesson, the standards for fire-retardant and non-combustible materials for vehicles running in subways and long tunnels were revised, and fire-prevention measures for vehicles were advanced. The main structural countermeasures for vehicles were as follows:
- Replacing interior materials with aluminum decorative panels.
- Replacing the glass in through-doors with wired glass to prevent glass from breaking and fire spreading to adjacent cars.
- Making the gangway partitions fire-retardant to prevent fire from spreading to nearby cars.
- Making sleeper cars and dining cars connected to sleeper trains fire-retardant.
- Attaching stickers to specify the maintenance of in-car public address equipment and restrictions on the use of in-car emergency buzzers.
- Installing or adding fire extinguishers to vehicles.
- Installing smoke detectors in sleeper cars and providing portable emergency lights and megaphones.
- Attaching automatic fire-extinguishing systems to sleeper cars with diesel engines under the floor.
Although it was unclear what measures should be taken in the event of a train fire in an existing long tunnel, lessons from this accident led to the designation of tunnels of 5 km or more in length as long tunnels (13 conventional lines and 7 Shinkansen lines, 20 locations in total at that time), and the following emergency measures were implemented:
- Countermeasures for poor reception of crew radios, improvement of wayside telephones, improvement of lighting equipment, and maintenance of fire extinguishers.
- Stationing diesel locomotives or motor cars near long tunnels.
- Reviewing the rescue system and manuals for handling fires, especially the rule that "in the event of a fire inside a tunnel, the train must not stop inside the tunnel."
In addition, for semi-long tunnels with many train passages, information communication equipment, evacuation guidance equipment, and lighting equipment were improved, and the same measures as for long tunnels were implemented, including countermeasures for poor crew radio reception and improvement of wayside telephones.
Taking this accident seriously, Japanese National Railways invited outside experts and established a "Railway Fire Countermeasures Technical Committee." In December 1972, a combustion test on a stationary train was conducted at the Oyunagaya factory. In August 1973, a combustion test on a moving train was conducted on the Nemuro Main Line. In October 1974, the world's first combustion test using a moving train inside a tunnel was conducted in the Sarutoge Tunnel on the Miyako Line (now the Sanriku Railway Kitarias Line). From the results, it was proven that it is safer to stipulate that "in the event of a fire inside a tunnel, the train does not stop, but keeps running with all through-doors, windows, and ventilators of the burning car closed, and escapes from the tunnel," rather than the previous rule that "trains must stop immediately in all cases." The operating regulations were revised accordingly. The rule is that the train must not stop inside or outside a tunnel, or on a bridge or elevated viaduct.
Furthermore, fire-retardant construction work, as described above, was carried out so that combustion could be prevented until the train escapes the tunnel even if a fire occurs in a long tunnel like the Hokuriku Tunnel.
As an example of the lesson being applied, on March 30, 1988, when a fire broke out on the "Salon Express Aruka Dea" in the section between Echigo-Nakazato Station and Iwappara Ski-jō-mae Station, which had many tunnels, the train emerged from the tunnel and made an emergency stop. Before this accident, in 1969, a fire also broke out on the sleeper limited express "Nihonkai," which was passing through the Hokuriku Tunnel. On that occasion, however, the train crew used their ingenuity to disregard the regulations then in force and moved the train out of the tunnel, allowing firefighting to begin promptly. Because of this, no casualties occurred. However, Japanese National Railways considered this a "violation of regulations," disciplined the crew, and did not review the operating manual. As a result, the accident train had no choice but to stop in the middle of the long tunnel as the regulations required, which led to the great disaster.
In court, no responsibility was pursued against JNR executives for this accident. However, as a consequence of the large number of victims, the driver and two conductors were prosecuted for professional negligence resulting in death and injury. In the trial, which lasted a long time over issues such as the argument that stopping the train inside the tunnel had enlarged the damage, the Kanazawa District Court ruled on November 25, 1980, that the crew's conduct at the time of the accident was regarded as "compliance with the regulations and doing their best." In addition, regarding the separation of brake pipe hoses during the separation work, the driver's delays due to "clumsy work" were deemed within an acceptable range, and both were acquitted. Furthermore, the disciplinary action against the crew of the "Nihonkai" that had occurred before this accident was also withdrawn.
At the time, six cars of the Oshi 17 type, the same as the accident car, were on the register. However, the day after the accident, they were withdrawn from all train operations (at the time used only on "Kitaguni" and on one round trip of the express "Towada" between Ueno and Aomori). Except for car 2018, which was damaged and kept as evidence for the trial, all cars were scrapped or converted into training cars, and they were retired by 1974. (Car 2018 was scrapped in 1981 after the trial concluded. Car 2051 was kept at Kanazawa Operating Depot until around 1980 for on-site inspection for the trial.)
Even before this accident, the dining cars of night express trains had already been reduced, but the scrapping of all Oshi 17 cars caused dining cars to disappear from night express trains. The short circuit in the electric heating wiring that caused the fire could occur in any vehicle that uses electric heating, so the Oshi 17 type did not have a uniquely high risk. However, the Series 10 passenger cars made extensive use of newly developed plywood and plastic interior materials to reduce weight, which generated toxic gases and was one cause of the expanded casualties. Furthermore, the lights mounted on the tunnel walls in long tunnels had been switched off during normal operation before this accident, because the National Railways Labor Union (Kokuro) and the National Railways Motive Power Union argued that they "obstruct the crew's view." After this accident, however, the problem was revealed in emergency situations, and the lights were changed to remain on at all times.
The Series 14 passenger cars, new sleeper cars manufactured from 1971, were also pointed out as a safety problem because they had diesel engines mounted under the floor, so production was temporarily halted and switched to the Series 24, which used centralized power supply. Later, production of the Series 14 (type 15), which incorporated fire-safety measures, began in 1978, and the same fire countermeasures as the Series 14 (type 15), such as installing automatic fire-extinguishing systems, were also implemented on the existing Series 14 (type 14). Among the older passenger cars used on night express trains other than "Kitaguni," the seating cars, such as the Series 10 and Suha-type Series 43 cars, were gradually replaced from 1973 by the Series 12 cars with enhanced fire retardancy as the older cars deteriorated. However, due to financial difficulties and other reasons, the replacement was not completed until the timetable revision accompanying the opening of the Joetsu Shinkansen in November 1982. As for sleeper cars, there were no replacement vehicles, so they continued to be used, but most were gradually replaced by the Series 20 1000 and 2000 numbers. These were also replaced by the Series 14 cars, as seating cars and converted Series 20 cars on express services were all replaced by 1983. They were also scrapped entirely by 1985 when used on long-distance local trains. In addition, starting in the same year, "Kitaguni" was changed to be operated by the Series 583 electric multiple units.
Other
The rescue story of this accident was later introduced by NHK in its program "Project X" as "Rescue from a Train Fire: The Hokuriku Tunnel Fire."
Years later, when the Sekisui Metal (KATO), a major railway model manufacturer, released the Series 10 passenger car (N scale), the accident car "Oshi 17 2018" was selected as the prototype and was commercialized. This was not because the car number of the accident had been deliberately chosen. Rather, the Oshi 17 car that remained on the register until the end was number 2018 (which had been preserved as evidence of the accident).