Questions about High Speed Railways

[L&Y Robert]

Another accident, Spain this time. Why are we all so keen on going faster? Is High-speed Rail really practicable? How fast is too fast? I remember lessons in the physics lab - the faster an object moves, the more energy there is stored in the momentum - so if a fast-moving object comes off the rails it is a bigger event than if a slow-moving one comes off the rails. It seems to me that the costs outweigh the benefits. Is there an ultimate limit for steel wheel on steel rail?

 

[DD]

No the bigger question is why was there no overspeed protection for such a drastic change in speed

 

[Zoidberg]

... Why are we all so keen on going faster?

To get somewhere more quickly.

Is High-speed Rail really practicable?

Yes. It's in operation and can be seen to work.

How fast is too fast?

As determined by various factors
- capability of the equipment (including rolling stock, track, lineside)
- environmental conditions (e.g.weather)

As per post #2, automated processes ought to be implemented as far as possible to prevent excess speed for given circumstances.

 

[Trog]

Another accident, Spain this time. Why are we all so keen on going faster? Is High-speed Rail really practicable? How fast is too fast? I remember lessons in the physics lab - the faster an object moves, the more energy there is stored in the momentum - so if a fast-moving object comes off the rails it is a bigger event than if a slow-moving one comes off the rails. It seems to me that the costs outweigh the benefits. Is there an ultimate limit for steel wheel on steel rail?

I was once riding on a brake van being hauled by a PABC in working drive that derailed on a twist fault at less than 1MPH, do you suggest we ban very slow trains as well? As the gyroscopic action of the wheel sets will not work so well at these speeds. (I did physics at skool to ya know).

 

[ainsworth74]

Is High-speed Rail really practicable?

Judging by the thousands of miles of high speed railway around the world the answer would appear to be an emphatic yes.

How fast is too fast?

Too fast is when you exceed the speed for which the vehicles in question have been rated and when you exceed the safe operating speed of the line on which you're travelling. No more, no less.

It seems to me that the costs outweigh the benefits.

What costs are your referring to?

Is there an ultimate limit for steel wheel on steel rail?

Probably though I doubt we've reached it yet.

 

[SS4]

Another accident, Spain this time. Why are we all so keen on going faster? Is High-speed Rail really practicable? How fast is too fast? I remember lessons in the physics lab - the faster an object moves, the more energy there is stored in the momentum - so if a fast-moving object comes off the rails it is a bigger event than if a slow-moving one comes off the rails. It seems to me that the costs outweigh the benefits. Is there an ultimate limit for steel wheel on steel rail?

1) To get to places more quickly. Time is money
2) Yes and it's in use
3) Depends on a number of factors but mainly weather IMO
4) There will be a limit and extensive testing takes place to find said level.

I see this as a tragic accident but not one that should be used as emotional blackmail in order to curtail high speed rail.

If we go to the roads would you suggest making the speed limit on motorways 35mph? From the physics lab energy required to stop is proportional to speed squared so halving speed requires 4x less energy and is safer.

 

[Darandio]

Another accident, Spain this time. Why are we all so keen on going faster? Is High-speed Rail really practicable? How fast is too fast? I remember lessons in the physics lab - the faster an object moves, the more energy there is stored in the momentum - so if a fast-moving object comes off the rails it is a bigger event than if a slow-moving one comes off the rails. It seems to me that the costs outweigh the benefits. Is there an ultimate limit for steel wheel on steel rail?

Why didn't you end your post with #hs2?

 

[pablo]

Too fast is when you exceed the speed for which the vehicles in question have been rated and when you exceed the safe operating speed of the line on which you're travelling. No more, no less......

Are you overlooking crashworthyness?

 

[Oswyntail]

Are you overlooking crashworthyness?

I would hope that was included in the "rating"

 

[Deerfold]

There was an interviewee on the Today programme this morning.

Whilst agreeing that we may learn useful things that can help improve rail safety in the future from the tragic accident in Spain she also pointed out that we have a mean of one passenger death every three years in this country, compared with one death on the roads every 5 hours.

 

[YorkshireBear]

Are you overlooking crashworthyness?

Yes as does every other transport sector... Planes would never take off! Cars dont survive crashes at 70mph very well yet they are still driven every day.

 

[Bungle73]

Another accident, Spain this time. Why are we all so keen on going faster? Is High-speed Rail really practicable? How fast is too fast? I remember lessons in the physics lab - the faster an object moves, the more energy there is stored in the momentum - so if a fast-moving object comes off the rails it is a bigger event than if a slow-moving one comes off the rails. It seems to me that the costs outweigh the benefits. Is there an ultimate limit for steel wheel on steel rail?

Why do you say "another accident" like these incidents are happening all the time? They are not. Both the French TGV network and Japan hgh speed rail network have operated for decades with no fatal incidents.

In the EU alone roughly as many people are killed on the roads every single day (on average) as appear to have sadly died in this accident.

 

[Geezertronic]

Am I correct in saying that the last passenger death due to a rail accident on the British rail network was 2007 at Grayrigg?

 

[YorkshireBear]

Am I correct in saying that the last passenger death due to a rail accident on the British rail network was 2007 at Grayrigg?

As far as i know yes. And before that it was November 2004.

(do we count the incident in Liverpool???)

 

[Geezertronic]

(do we count the incident in Liverpool???)

I did consider that but wouldn't consider it as a result of an accident caused by Infrastructure or vehicle fault, although the Liverpool incident was classed as rail staff human error which it looks like the Spain accident was as well (at this time anyway)

 

[tbtc]

Another accident

Why do you say "another accident" like these incidents are happening all the time? They are not. Both the French TGV network and Japan hgh speed rail network have operated for decades with no fatal incidents.

In the EU alone roughly as many people are killed on the roads every single day (on average) as appear to have sadly died in this accident.

Totally agree with Bungle73 here - really annoys me when people's immediate reaction is "another accident" and straightaway suggest that SOMETHING MUST BE DONE. A dozen people die on the UK's roads each day, but nobody suggests anything be done about it.

Am I correct in saying that the last passenger death due to a rail accident on the British rail network was 2007 at Grayrigg?

As far as i know yes. And before that it was November 2004.

(do we count the incident in Liverpool???)

So one death in almost a decade? When thousands have died on the roads in the same time? If you ask The Great British Public, I wonder what their estimated figures would be?

 

[YorkshireBear]

Totally agree with Bungle73 here - really annoys me when people's immediate reaction is "another accident" and straightaway suggest that SOMETHING MUST BE DONE. A dozen people die on the UK's roads each day, but nobody suggests anything be done about it.





So one death in almost a decade? When thousands have died on the roads in the same time? If you ask The Great British Public, I wonder what their estimated figures would be?

I think we should count Liverpool so actually tbtc its 2. Can't believe you'd lie like that.

Surprising though when people question me on it. I say that back to them and there response usually? 'Yeah but its different for Roads'

To which I usually shake my head and respond with 'I can't talk to someone who thinks people dying is okay'. Win.

 

[edwin_m]

In any case the accident in Spain was not on a high speed line - I understand it was on a low speed section just after the end of the high speed line. I'm pretty sure no passenger has ever been killed in an accident on a high speed line. They have ATP systems to enforce safe speeds, very gentle curvature, and no level crossings so most of the causes of accidents are eliminated.

 

[rebmcr]

In any case the accident in Spain was not on a high speed line - I understand it was on a low speed section just after the end of the high speed line. I'm pretty sure no passenger has ever been killed in an accident on a high speed line. They have ATP systems to enforce safe speeds, very gentle curvature, and no level crossings so most of the causes of accidents are eliminated.

China.

 

[broadgage]

There are thousands of miles of high speed railway, with a good safety record.
Nothing is absolutely safe, but rail is certainly safer than road transport, and high speed lines seem at least as safe as lower speed ones since they are better built and often have fewer oportunities for acces by animals and vehicles.

No one knows what the absolute limiting speed is for more or less conventional railways, but about 300MPH has been suggested.
Beyond about 300MPH the energy and other costs start to become similar to the costs of flying rendering the idea not actualy impossible, but a bit pointless.
I have no doubt that 300MPH will eventualy be exceeded for test or record breaking purposes, but rather doubt that we will ever see regular operation at much more than 300MPH.

Still higher speeds could be achieved with maglev and linear motor drive, but is not really conventional high speed railway.

The ultimate speed limit for any ground transport system is the speed of sound which is about 750MPH, higher speeds could be achieved but would not be reaslistic on account of sonic booms. High flying supersonic aircraft are bad enough, imagine that a ground level.

 

[rebmcr]

The ultimate speed limit for any ground transport system is the speed of sound which is about 750MPH, higher speeds could be achieved but would not be reaslistic on account of sonic booms. High flying supersonic aircraft are bad enough, imagine that a ground level.

There's no feasible upper limit for Maglev inside a vacuum tube.

 

[Bungle73]

In any case the accident in Spain was not on a high speed line - I understand it was on a low speed section just after the end of the high speed line. I'm pretty sure no passenger has ever been killed in an accident on a high speed line. They have ATP systems to enforce safe speeds, very gentle curvature, and no level crossings so most of the causes of accidents are eliminated.

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

 

[gordonthemoron]

In any case the accident in Spain was not on a high speed line - I understand it was on a low speed section just after the end of the high speed line. I'm pretty sure no passenger has ever been killed in an accident on a high speed line. They have ATP systems to enforce safe speeds, very gentle curvature, and no level crossings so most of the causes of accidents are eliminated.

Eschede, Germany 101 dead, although that was a a track failure

 

[Bungle73]

Eschede, Germany 101 dead, although that was a a track failure

It wasn't, it was a cracked wheel, like the page I just posted explains.

 

[ainsworth74]

I have no doubt that 300MPH will eventualy be exceeded for test or record breaking purposes, but rather doubt that we will ever see regular operation at much more than 300MPH.

The current world record is 357.2mph acheived in 2007 by a shortened TGV set.

Eschede, Germany 101 dead, although that was a a track failure

I thought Eschede was a due to a wheel tyre failing and then interacting with pointwork?

 

[edwin_m]

China.

Yes you're right of course. Have to qualify that statement with "in Europe" now.

 

[Bungle73]

Yes you're right of course. Have to qualify that statement with "in Europe" now.

But it's still wrong, as I already pointed out.

 

[ainsworth74]

Yes you're right of course. Have to qualify that statement with "in Europe" now.

As above: Eschede

 

[YorkshireBear]

Do we build high speed trains out of aluminium still as I believe the massive crumple was in part due to this? Might be remembering incorrectly.

 

[87015]

As above: Eschede

That was on the Hamburg-Hanover conventional line rather than a 'HBS' dedicated high speed line.