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davidg

French To Reduce Speed Of Tgvs

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According to information leaked to l'Express magazine TGVs on French railways will run slower from 2018 when a new series of trains will be delivered. The aim is to save money due to wear and tear on carriages and catenary. The new trains will certainly be 20kph slower, running at a still very fast 300 kph but there is an internal lobby suggesting aligning with German railway's 250kph or even 200kph!

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surely the pantographs touch the catenary cables for the length of the journey, whatever the speed? Heat maybe?

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It could be heat as catenary breakages seem more common in the south.

It is a bit of a shame when we go backwards technologically I think (like the loss of Concorde) but maybe it is a pragmatic choice - cost of running vs journey times.

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The new trains will certainly be 20kph slower, running at a still very fast 300 kph but there is an internal lobby suggesting aligning with German railway's 250kph or even 200kph!

Shame if they're being reduced to the lowest common denominator of speed. Is this a new EU directive, perhaps? If so, when will they be reduced to the UK's mean railway speed of 30mph? :unsure:

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Sensible policies for a happier EU.

everybody not owning transportation of artificial propulsion can now apply for job as administrator of such device for 35 hours pe week(with 1 hour per day lunch break) waving red flag in front of said contraption.

hey presto, full employment.

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According to information leaked to l'Express magazine TGVs on French railways will run slower from 2018 when a new series of trains will be delivered. The aim is to save money due to wear and tear on carriages and catenary. The new trains will certainly be 20kph slower, running at a still very fast 300 kph but there is an internal lobby suggesting aligning with German railway's 250kph or even 200kph!

British Rails Inter City 125 could do 200 kph back in 1975.

In fact it could go as fast as 238 kph.

http://en.m.wikipedia.org/wiki/InterCity_125

If that speed is mandated across Europe then it undercuts a lot of the hype for HS2

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It could be heat as catenary breakages seem more common in the south.

It is a bit of a shame when we go backwards technologically I think (like the loss of Concorde) but maybe it is a pragmatic choice - cost of running vs journey times.

Could be simple wear and tear.

Totally subjective, but I've been using the TGV (Atlantique) and the Eurostar on and off since they were introduced. The ride on both is now noticeably worse than when they were brand new.

I also remember that when the Eurostar was new and shiny, I travelled a few times on the TGV to Paris, then hopped onto the train to Waterloo (that choice of station still makes me smile!) and the Eurostar was clearly a smoother ride. At the time I assumed it was the improving technology, but now I'm not so sure - I think it was simply down to the TGV being a decade older, and more worn.

Certainly I can't imagine these trains lasting 50 years, like so much of the rolling stock that we have to put up with (on the both sides of the Channel, incidentally!).

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everybody not owning transportation of artificial propulsion can now apply for job as administrator of such device for 35 hours pe week(with 1 hour per day lunch break) waving red flag in front of said contraption.

hey presto, full employment.

Don't forget the free case of wine at Christmas and in June. And exemption from the taxes of ALL member states.

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Certainly I can't imagine these trains lasting 50 years, like so much of the rolling stock that we have to put up with (on the both sides of the Channel, incidentally!).

Give me the old stuff over any of the new crap. Only decent train journey I've had in recent years was on an HST.

20 kph slower will make precious little difference to anyone's life so if there's quite a saving in doing so it makes sense. I honestly doubt most people would even notice.

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History of the TGV makes an interesting read

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

I didn't know they were originally designed to be powered by gas turbines but changed to overhead electricity from nuclear due to the 74 oil crisis.

Also Mitterand insisted ticket prices were the same for all.

Love the French.

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Energy consumption increases exponentially as speed increase (The biggest cost with anything above about 60mph is air resistance). Dropping the speed slightly will have a big impact on the green credentials of trains. My guess is this is a euro lobby thingy

IIRC a rule of thumb for cars is that, above 60mph, wind resistance is the biggest factor, as opposed to friction in the engine and transmission, and that this increases with the cube of speed - so power has to increase massively for small increments at high speed.

i would think it is less of a problem with trains, because they are long and thin. or maybe it makes no difference, it is the frontal aerodynamics that matter. I wonder if the pantograph and wheel bogey design makes a significant difference to the Cd.

I read a BBC 'article' last week about the 'designer' of the HS125 back in the 1970's. By 'design' they mean soft furnishings and the bodywork. I got the impression that very little science went into the aerodynamics of the locomotive.

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IIRC a rule of thumb for cars is that, above 60mph, wind resistance is the biggest factor, as opposed to friction in the engine and transmission, and that this increases with the cube of speed - so power has to increase massively for small increments at high speed.

i would think it is less of a problem with trains, because they are long and thin. or maybe it makes no difference, it is the frontal aerodynamics that matter. I wonder if the pantograph and wheel bogey design makes a significant difference to the Cd.

I read a BBC 'article' last week about the 'designer' of the HS125 back in the 1970's. By 'design' they mean soft furnishings and the bodywork. I got the impression that very little science went into the aerodynamics of the locomotive.

Some years ago I got involved with a project in partnership with a guy who had studied automotive design at uni. I was stupefied by the fact that basic maths was beyond him. It turned out that automotive design was an arts degree, not an engineering degree.

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i would think it is less of a problem with trains, because they are long and thin. or maybe it makes no difference, it is the frontal aerodynamics that matter. I wonder if the pantograph and wheel bogey design makes a significant difference to the Cd.

The aerodynamics at the front and back will make a difference although proportionally less than in a car, since the overall power available will be much greater. It seems that people don't bother much with train aerodynamics below about 90-100 mph, but above that some consideration is given (even going back to steam days).

I read a BBC 'article' last week about the 'designer' of the HS125 back in the 1970's. By 'design' they mean soft furnishings and the bodywork. I got the impression that very little science went into the aerodynamics of the locomotive.

What I read on Wikipedia (probably about as reliable) was that he was hired just to do the livery but ended up designing the whole shape, but working with the aerodynamics guys, if it's the same guy. The HST was probably about the last change on the rail network that was worth having IMO, everything else since makes me wish I could go back in time (OK, the stations aren't anywhere near as tatty now too).

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The aerodynamics at the front and back will make a difference although proportionally less than in a car, since the overall power available will be much greater. It seems that people don't bother much with train aerodynamics below about 90-100 mph, but above that some consideration is given (even going back to steam days).

What I read on Wikipedia (probably about as reliable) was that he was hired just to do the livery but ended up designing the whole shape, but working with the aerodynamics guys, if it's the same guy. The HST was probably about the last change on the rail network that was worth having IMO, everything else since makes me wish I could go back in time (OK, the stations aren't anywhere near as tatty now too).

As an engineer I cringe when I hear people described as a 'designer'. It often means a person who has no grasp of engineering principles.

Good aesthetic design is desireable, and even essential for a commercial product, but it usually takes someone else with a good grasp of engineering to make that product possible. If a 'designer', say, comes up with a car body shape, it is an engineer who has to fit the mechanicals inside, and make a body of that shape comply with structural requirements such as crash rigidity. Often the engineer is not the 'designer'.

Unfortunately the public have little grasp of what engineering is, and pay attention only to the outward appearance of a product. That is what sells the product. That is why Apple sues Samsung about the shape of the rounded corners on mobile phones, FFS. As if that was the real leap of genius that goes into a mobile phone.

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The bit I read sounds exactly like that was the sort of guy involved, and because he knew that himself he worked with the aerodynamics guys. The result was something that had both, is iconic and probably the only non-steam train that's ever managed to enter public imagination. For that reason it's great news that a team has got one of the prototype power cars running again (unfortunately the other was scrapped long ago).

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