Bullet Train Derails In China

chrb writes "Xinhua is reporting that a Chinese bullet train has derailed, resulting in two of the train's coaches falling off a bridge. This comes only a few months after officials at the Railways Ministry expressed concerns that builders had ignored safety standards in the quest to build faster trains in record time — a claim that was subsequently retracted."

Comments

Collision

[robertl234]

According to reports, a lightning strike caused the first train to lose power and was subsuequently rear-ended by a second train.

Re:Collision

[Aboroth]

Presumably, there should have been some kind of safety system in place to deal with a relatively common natural phenomenon called lightning. Or, just the amazingly easy to predict general problem of power loss. But clearly, you are correct, the Chinese can do no wrong here.

Re:Collision

[Dachannien]

Actually, it happened on Washington, DC's Metro system two years ago. A problem with a train proximity sensing system resulted in a failure to engage automatic braking on one train when it approached another train farther ahead that had broken down. In that case, there was evidence that the operator, shortly before her death, had attempted to stop her train manually, but didn't have enough advance warning to stop in time. Eight other people were killed, and in response, WMATA ordered operators to run their trains in manual mode at all times.

Re:Collision

[Chep]

you can't actually read the signals, when the train travels > 250km/h. Even in 1980, designers of the TGV (270 then, 320-350km/h now) knew this, and the signalling is done using what is called cab-signal, which puts the display within the cabin.

Some slower but WAY busier lines also need to get away with the old block system, in order to reduce the spacing. In Paris, the two primary suburban lines (RER A and B) use what is called 'permissive' spacing, (SACEM on A, KVBP or KCVP on B), in order to reduce space between trains -- SACEM can space trains under 5 meters apart under stressed conditions.

But the key point of these advanced signalling systems is that the train-spacing software MUST be perfect. Not just "bug-free, we tested and deployed and ITIL'd the thing to death" but "mathematically proven bug-free". And even that doesn't cut it. Read up on how the SACEM hardware works, for instance. Or on the "Methode B" used to design the SACEM and the SAET (the latter of which powers automatic lines such as M14 and now M1 in Paris. SAET can safely take even a 110 year-old manually driven train within the robotic shuttle traffic, and get everyone safe there).

Back to China, perhaps the strike broke some communication line, making the position of the stopped train 'unknown'. But if that happened, someone much worse must have happened as well.

Perhaps, by cutting corners everywhere, they've also cut on the provably bug-free programming which one MUST use to build the train-spacing software. THAT, if that happened, is criminal.

Perhaps they've cut corners on brakes. Or whatever.

Hopefully for them, that's a fixable bug....

Compare to Japan's Bullet Train

[vinng86]

During the Shinkansen's 45-year, nearly 7 billion-passenger history, there have been no passenger fatalities due to derailments or collisions,[13] despite frequent earthquakes and typhoons.

http://en.wikipedia.org/wiki/Shinkansen#Safety_record

Re:Compare to Japan's Bullet Train

[Anonymous Coward]

Contrary to the South Park episode, Japan and China are in fact two different countries

Lightning involved

[MagikSlinger]

I don't know if it is necessarily corner cutting, but one would have thought lightning protection would have been one of the obvious things they would have engineered. From the articles, the lightning strike disabled the train and the train behind slammed into it. Also, if a train is stalled on the track, one would think there would be someway of knowing; either through telemetry or the driver radioing "Help! My train's stuck!". So if so, why didn't the other train stop? Lots of questions... I wonder if we will ever truly learn the answers or will this become another of China's "let's sweep it under the carpet" moments?

Re:Lightning involved

[Anonymous Coward]

It was proposed (by Siemens Signals gmbh) that a modified TVM430 system be used in China. This is what is used on the more modern TGV lines in France. It was rejected by the Chinese Railways as being too expensive so they came up with their own.
The TVM430 uses a moving block system. This means that this accident could never have happened. This system leaves at least one complete signal section between trains. The sections are also long enough for a SPAD (signal passed at danger) that will cause an application of the brakes to AUTOMATICALLY happen to stop the train from well in excess of the normal line speed before it would slam into the back of the train that was stopped on the line.

If my experience with the Chinese Bullet train lines is anything to go by, the phrase 'held together by duck tape' seems very apt.
The trains themeselves might be good but the PW (Permanent Way) is very sub standard. The last time I travelled on one the ride quality remined me of the line from Euston to Rugby in the 1980's. Think bucking bronco.

This was an accident waiting to happen.

Anon, ex staffer with Westinghouse/Siemens Signal Systems (UK) but still employed in the Railway Business.

   

Design difference with TGV

[Midnight Thunder]

My cynical nature seems to be not surprised about "that builders had ignored safety standards", in China.

One thing that should be mentioned is looking at the photos of the Chinese bullet train, is that the design did not inspire itself on one of the key advantages of the French TGV. That advantage being that the bogies are between the carriages and not under each carriage. Apparently the French designed it that way because it reduces the scope of damage due to derailment. The TGV has derailed, but it always derails in a straight line.

ref: Nova: Looking down the track at very fast trains

Re:Design difference with TGV

[MORB]

And it works incredibly well. The TGV had several high speed derailment that all caused only minor injuries.

It includes the world's fastest derailment at 294kph (182mph) where only one person was slightly injured.

http://en.wikipedia.org/wiki/TGV_accidents