A brief 12-15 seconds before a massive earthquake of 8.9 magnitude hit mainland Japan on the afternoon of 11 March 2011, a seismometer at Kinkazan belonging to the country's eastern rail operator JR East sent an automatic stop signal to the Shinkansen - Japan's high-speed bullet train - electric power transmission system, triggering the emergency brake on 33 trains.

Industry experts agree that critical damage and, more importantly, great sorrow was averted due to the installation of such seismometers - the one at Shinkansen is one of nine along the Pacific coast - alongside the completion of anti-seismic reinforcement works such as quakeproof structures and anti-derailing systems that were undertaken based on the experience of the 1995 Great Hanshin-Awaji and 2004 Niigata Chuetsu earthquakes.

"Various kinds of solutions have been executed in the Japanese railway system based on previous experiences of disasters and accidents," says Mitsubishi Research Institute senior consultant and expert in railway development, Takeshi Fukayama. "Many of those solutions worked in this case and prevented, for example, the Shinkansen from suffering serious damage."

JR East's international department director Mitsuo Higashi agrees. Speaking in the May edition of International Railway Magazine, he said: "No critical damage to major structures was caused because of the anti-seismic reinforcements we had undertaken."

JR East's urgent earthquake detection and alarm system (UrEDAS) is made up of seismometers installed at 97 locations. As with the Shinkansen seismometer, when they detect earthquake-induced tremors, they determine the expected effect of the earthquake and send out warning signals to cut the power supply to the trains.

The physical damage

The quakeproof systems and reinforcement works couldn't, however, save the railways from avoiding any damage whatsoever.

"According to Higashi, only one train, running under test without passengers, derailed that day."

"Tracks were displaced in 2,590 places, and 1,150 electrification masts were broken, leaning or cracked," said JR East's Higashi in International Railway Magazine. He went on to describe the events as "extremely painful", adding that "the 11 March earthquake forced us to cancel, suspend or reduce train operations on most of our 7,512.6km network".

But Tokyo's network fared rather well, and JR East was able to recommence business on all its lines on 12 March, with interruptions only caused by electricity shortages.

"Scheduled blackouts led to fewer train operations than in the normal situations in the Tokyo metropolitan area," says Fukayama. "Many trains also stopped because of inspection and track maintenance on the day of the earthquake," he continues. "The number of the people who could not go home on that day in the Tokyo metropolitan area was reported as 2.6 million."

According to Higashi, only one train, running under test without passengers, derailed that day, when it was approaching Sendai, before it was immediately halted by the emergency braking.

Meanwhile, the system's catenary avoided serious damage and breaks in the contact wires were rare. Only sub-messenger and autotransformer protection wires were damaged.

Moving away from Tokyo itself, the Kanto region, which includes the Greater Tokyo Area, and Tohoku, a region to the north of Kanto, were more severely hit with 1,200 places suffering great damage and 325km of conventional lines washed away by the tsunami. "At costal railways such as the Sanriku Railway and the JR Senseki Line, some rolling stocks, many stations and tracks were completely flowed out by the tsunami," says Fukayama. Altogether 23 stations were washed away, tracks and bridge piers were either eroded or buried, and five passenger and two freight trains were derailed.

Rebuilding Japan's rail network

According to JR East, the recovery of the 325km of seriously damaged conventional lines will be difficult. "We will develop recovery plans that are consistent with the reconstruction plans of the local and national governments," said Higashi in International Railway Magazine. However, it will probably take years to recover the coastal areas, although the intention is to rebuild the railways along with news towns that were destroyed by the tsunami.

By comparison, the Tohuko Shinkansen bullet trains re-started operations only 49 days after the earthquake. Around 8,500 engineers worked round the clock - repairing points, train stations and tunnels - in order for the service to resume in time for the spring holiday season at the beginning of May.

"The Tohuko Shinkansen bullet trains re-started operations only 49 days after the earthquake."

"As the railway system is large and complex, the speed of restoration was incredible," says Fukayama. "It is said one reason for the early recovery was that we had less damage in the structures because of strengthening measures based on former earthquakes. Moreover, the railway operators and other people concerned made the recovery a first-priority project."

But other damage will not be as easy to repair. The earthquake and tsunami has been a bitter financial pill to swallow for the operator, which has been in the black since it was founded in 1987.

According to JR East international desk manager Emiko Sayama, the company listed a special loss of JPY5.8bn ($72.3m) in the 2010 results for the year that ended on 31 March 2011.

The civil engineering structures are covered by an earthquake insurance, which has a maximum payout of JPY71bn ($842m) and will compensate for the largest amount of the damage. "But the actual amount of money to be paid will be determined after our actual losses are carefully examined," explained Higashi.

The director of JR East's international department went on to say that the plan for FY 2011 would be worked out on the basis of last year's results: "As very significant reductions in revenue and increases in cost are expected, we must be prepared for extremely harsh figures for our revenue and expenditure forecasts for FY 2011."

Need for improvement

While various measures saved the railways from experiencing worse damage, Kimitoshi Sakai, earthquake and structural engineering researcher at the Railway Technical Research Institute, believes the country's railway operators must introduce a common standard of seismic countermeasures in order to be better prepared for any future disasters. Shortly after the earthquake, he wrote in the institute's Railway Technology Avalanche magazine that the measures taken after the earthquakes in 1995 and 2004 have been conducted independently from each other and hence their aseismic capability varies.

According to Sakai, improvements in earthquake safety for the whole railway system can only be reached when evaluated with a common standard to put countermeasures into practice, which have been determined on the basis of a rational principle. With a national system, seismic countermeasures could be put in place more cost-efficiently and be adjusted to the level of seismic activity in a specific area.

"This method allows the most appropriate countermeasures to be chosen for each target line by taking into account the seismicity, ground condition, structural conditions and the level of traffic," Sakai wrote.

Lessons to be learnt

Seeing pictures from the earthquake and the tsunami it is hard to believe that not one passenger died on any of the numerous trains in operation throughout the country that day, especially as Japan's rail network - including all the conventional lines as well as that of the high-speed bullet train, Shinkansen, the heart of the Japanese railway system - covers 27,500km and carries around 22.5 billion passengers every year.

"Actions have to be taken on an industrial, scientific and political level to be prepared for any future events."

However, the fact that the system survived largely intact does not mean operators will be complacent.

As a result, the earthquake and tsunami of March 2011 will not only show in financial figures of JR East, but also have an impact on the company's internal processes. According to Higashi, research on the events has to be conducted and lessons from 11 March have to be learnt. "We will determine the effectiveness of the measures that we have taken and decide what should be done in the future," he says.

Higashi believes that the training of train staff and crews is particularly important. Regular preparation has resulted in a mostly smooth evacuation this time but the quality has to be further improved.

Fukayama agrees, saying that Japan has to learn lessons from the disaster. He believes that actions have to be taken on an industrial, scientific and political level to be prepared for any future events - but hopes that better preparation will not be put to the test any time soon.