JR East Prepares for a Large Scale Earthquake
East Japan Railway Company
October 19, 2005
The earthquake in Chuetsu, Niigata Prefecture, which struck on October 23, 2004, caused a great deal of damage to JR East facilities, including derailing the Joetsu Shinkansen Toki No. 325, deforming tracks, causing bridges and viaducts to subside, tilting electric poles and damaging tunnels, piers and snow disposal bases.
Since then, JR East has made good use of the lessons provided by this earthquake. Various surveys have been conducted on railway structures and aseismatic reinforcement plans have been drawn up and implemented ahead of schedule, with the aim of minimizing earthquake damage in the future. In addition, Shinkansen derailment phenomena have been investigated and countermeasures, such as improvement of systems to make trains stop even one second faster than before at the time of an earthquake, have been considered and some have already been completed.
As we near the one-year mark since the Niigata Chuetsu Earthquake, the approaches taken thus far, as well as future measures, are summarized below.
- Progress of Aseismatic Reinforcement Measures
Based on an assessment of the damage caused by the Hanshin-Awaji Earthquake in 1995 and the Sanriku-Minami Earthquake in 2003, JR East is performing aseismatic reinforcement on 18,500 Shinkansen rigid-frame viaduct columns and 12,600 conventional line rigid-frame viaduct columns that require countermeasures.
At the time the earthquake in Chuetsu, Niigata Prefecture struck, aseismatic reinforcement on 8,100, or 44%, of the 18,500 Shinkansen viaduct columns had been completed, and as of the end of September 2005, a total of 16,500 columns or 89% had been reinforced. Aseismatic reinforcement of locations where the space below viaducts is not used was also completed as of the end of September, and work on the remaining 2,000 columns in locations where the space below viaducts is used for station buildings, shops, offices and other buildings will be completed by the end of fiscal 2007, one year earlier than originally planned.
(2) Conventional lines
Aseismatic reinforcement at locations where the space below viaducts is used is currently underway and work has been completed on a total of 10,000 columns, or 79% of the subject locations. Aseismatic reinforcement of the remaining 2,600 columns will be completed by the end of fiscal 2008.
See Supplement 1 for details.
- Measures for Locations Similar to Those Damaged by the Niigata Chuetsu Earthquake
(1) Aseismatic reinforcement of Shinkansen tunnels located near active faults
The earthquake in Chuetsu caused the concrete lining to collapse and the tracks to buckle. Therefore, the Committee for Investigating the Causes of Railway Tunnel Damage in the Earthquake in Chuetsu, Niigata Prefecture (Chairman: Professor Toshihiro Asakura, Kyoto University Graduate School) has clarified the causes of the damage and investigated measures for reinforcing railway tunnels. JR East is promoting aseismatic countermeasures for Shinkansen tunnels based on these results.
Specifically, aseismatic reinforcement plans for tunnels will be drawn up in the future for Shinkansen tunnels that are within approximately 5 km from an active fault, basing site selection on the necessary countermeasure work as well as geological, structural and other factors involved.
(2) Aseismatic reinforcement measures for Shinkansen tunnels that intersect active faults
Based on the survey results, back-fill grouting for voids behind linings will be carried out within the current fiscal year for two of the Shinkansen tunnels that intersect active faults.
(3) Measures for locations similar to the No. 3 Wanazu Viaduct
The No. 3 Wanazu Viaduct sustained damage because buildings that use the space below the viaduct restrained the center portions of the viaduct columns. Therefore, 91 Shinkansen viaduct columns that are similar to the No. 3 Wanazu Viaduct will be reinforced by the end of fiscal 2006.
See Supplement 2 for details.
- Shinkansen Early Earthquake Detection System Improvement
The following improvements are being made to the Shinkansen Early Earthquake Detection System, which quickly detects when an earthquake has occurred and brings Shinkansen trains to a halt.
(1) Changes to the Operating Rule Criteria (SI index): Completed as of September 2005
(2) Changes in the method for estimating earthquake scale, etc: Scheduled for completion by the end of FY2005
(3) Addition of a function for stopping power transmission over the range affected by earthquakes: Scheduled for completion by the end of FY 2005
(4) Increased installation of wayside seismometers: Scheduled for completion by the end of FY2006
In addition, a system that shortens the time from when a power stoppage is detected until the brake command is issued, reducing this from 2 seconds to approximately 1 second, is being investigated for all Shinkansen rolling stock.
See Supplement 3 for details.
- Recovery Conditions of Shinanogawa Power Plant Facility Damage
The Shinanogawa Power Plant facility, which consists of three power plants—the Senju (5 generators), Ojiya (5 generators) and Shin Ojiya (2 generators)—and three sets of balancing reservoirs and tunnels, sustained damage to the balancing reservoirs and power facilities. In particular, balancing reservoirs whose dam bodies were damaged still cannot be used, and restoration work is continuing. A method that does not rely on the balancing reservoirs was used to restart one Senju generator from February 1, two Senju generators from February 28, and two Ojiya generators from April 10 of this year. However, the power generation level for this fiscal year is expected to be approximately 55% of normal, which means that train operation will remain inadequate to support the morning and evening rush hours in the Kanto region.
Restoration efforts are currently being made so that power generation using the balancing reservoirs can be restarted around spring of next year.
See Supplement 4 for details.
- Investigation of Shinkansen Derailment Phenomena during the Earthquake in Chuetsu, Niigata Prefecture and Derailment Countermeasures
A Special Committee for the Investigation of the Joetsu Shinkansen Derailment (Chairman: Executive Managing Director Masanori Tanaka) was organized in-house and conducted investigations to clarify the mechanisms of the derailment phenomena.
Currently, the Aircraft and Railway Accident Investigation Committee is working to clarify the derailment mechanisms that were involved, and the Shinkansen Derailment Countermeasure Council is conducting surveys and investigations into facility and rolling stock measures that can be implemented for the time being. However, the following mechanisms can be hypothesized at present based on the results of these JR surveys.
(1) Derailment was not caused by structural damage or subsidence and instead occurred due to seismic motion.
(2) Eleven axles derailed due to seismic motion, and the derailed wheels then damaged the tracks, which resulted in the derailment of a total of 22 axles.
(3) The train was guided by the rails even after derailment and the train position was maintained until the train stopped.
(4) The lead car tilted toward the center water drainage channel (between the in-bound and out-bound lines) due to destruction of the glued insulated joints in the rails.
Derailment countermeasures have also been investigated based on the findings of the Shinkansen Derailment Countermeasures Council, and JR East has entered the prototype stage for the following three items.
(1) Rolling stock guide mechanism
(2) Improvement of rail fasteners
(3) Improvement of glued insulated joints
See Supplement 5 for details.
- Approaches to Rescuing Passengers and Providing Information
The Earthquake in Chuetsu, Niigata Prefecture reaffirmed the importance of daily training and other efforts in the area of evacuating passengers from disaster-stricken rolling stock and in providing guidance. In addition, passengers in the disaster-stricken rolling stock strongly requested that information be provided concerning the location of the earthquake and conditions near their homes, so the following measures are being carried out.
(1) Passenger rescue training that assumes a large-scale earthquake
(2) Having on-board staff carry portable radios
(3) Increasing the number of dedicated cellular phones (JR phones) on Shinkansen rolling stock
Of these, (2) will be implemented starting from November 2005 as soon as preparations are completed and (3) will be implemented from around March 2006.
See Supplement 6 for details.
- Storage of Derailed Rolling Stock
To avoid forgetting the unprecedented derailment of Shinkansen stock due to an earthquake and to firmly maintain a corporate culture that places great emphasis on safety in the future, JR East is considering storing part of the derailed No. 325 Toki Series 200 railcars within the JR East General Training Center in Shirakawa City, Fukushima Prefecture.
• Reference Primary Damage Caused by Niigata Chuetsu Earthquake [PDF/166KB]