celestar
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Nose Shape Of A High Speed Train

Tue May 07, 2013 5:43 am

I am not an expert on high speed train but I am always curious to know more about it.
I noticed that in Japan, the Shinkansen, especially the newer model, has very long and slender nose, which in theory, helps aerodynamic but I really wonder if that is true? I was told that these shape are so unique that they are handmade by skill worker! If you look at TGV or ICE I/II/III they all have a modest nose shape, what is the reason of such difference? Japan Train Maniac?

I also wonder with such long nose on Shinkansen, the overhung from the tip to the wheel assembly, is that a problem for the turning track? I know such accident or issues was never reported but just curious to know if that will be a problem.
 
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Francoflier
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 6:24 am

It all depends on the level of efficiency you seek.

A train, given its size, has a ridiculously small cross section. This small frontal area footprint is being 'pushed' by the inertia of hundreds of tonnes of metal. Overall, aerodynamic efficiency is not as important on a train going 300kph than on an airplane going 900kph.

All high speed train have aerodynamic noses, but some will tend to be anally retentive about how many thousandths of a percent efficiency they can squeeze out of an aerodynamic profile.
Guess which camp the Japanese will be in...  

There is also a lenght and strenght constraint. Many high speed train are built to be run as coupled units. You can't have a nose too long or too intricate if you are going to fit a coupling mechanism in it.
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AF1624
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 6:49 am

Quoting francoflier (Reply 1):

A train, given its size, has a ridiculously small cross section. This small frontal area footprint is being 'pushed' by the inertia of hundreds of tonnes of metal. Overall, aerodynamic efficiency is not as important on a train going 300kph than on an airplane going 900kph.

All high speed train have aerodynamic noses, but some will tend to be anally retentive about how many thousandths of a percent efficiency they can squeeze out of an aerodynamic profile.
Guess which camp the Japanese will be in...  

This is a very valid explanation!

Also, the when they were both invented, the Shinkansen consumed much more power than the TGV an ICE per passenger/mile. I don't know about today. But I guess that would be a reason to try to squeeze as much resistance out as they could.

Then comes another subject which is simply aesthetics. It seems to me that the Shinkansen is one of the prides of Japan and as such, "deserves" to look very futuristic (this is, after all, the nation of robots). If you look at Shinkansen photos, you'll realise that there are a lot more that just one nose style. Whereas if you look at the TGV's, there are about three generations of noses and that's it.
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PHX787
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 6:50 am

The Shinkansen recently built is capable of going to 300 kph, and may push it to 320kph later on. The nose was specifically designed to be as aerodynamic as possible. Here's an example:
http://i42.tinypic.com/2jdp65e.jpg

The red train is the new one. The one on the left is also a Shinkansen but its not designed to run over 300kph. The aerodynamics have a huge difference. These things can be heavy so they need it to go faster.
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flyingturtle
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 7:08 am

Quoting francoflier (Reply 1):
There is also a lenght and strenght constraint. Many high speed train are built to be run as coupled units. You can't have a nose too long or too intricate if you are going to fit a coupling mechanism in it.

Yes, all European high speed trains I know of can be coupled.


Also, Japanese Shinkansen rail tracks were custom-made for that train. There are no other trains on these routes. In France and Germany, HST need to be compatible with routes constructed back in 1880, with all their turning radiuses and gradients. For example, the TGV Paris - Dijon - Pontarlier - Bern has to take the route through the Val de Travers in western Switzerland before joining the high-speed route just after Dijon. This picture is almost surreal:




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speedygonzales
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 8:48 am

Quoting flyingturtle (Reply 4):
Yes, all European high speed trains I know of can be coupled.

Not ICE 1, it only has an emergency coupling for towing.
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Stealthz
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 9:18 am

Quoting flyingturtle (Reply 4):
This picture is almost surreal:

Certainly is, what is driving this train?
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 9:59 am

There are a couple of other factors that come into play with the design of the nose and that is the pressure pulse that is generated as a train passes another object, generally another train going in the opposite direction or a tunnel. It's why passengers are told to stay away from the platform edge as fast trains pass by, its not that you'll be blown away, but may sucked towards the train by the low pressure.

Two high speed trains passing each other can generate a huge amount of suction between them at the nose, because of the low pressures there, so having a longer nose helps spread this out a bit and reduce the area of minimum pressure. If not the trains could be pulled towards each other, or some instability set up by the rapid sideways pressure pulse. From what I read the trains carry many tonnes of ballast to avoid this eventuality.

Trains going into tunnels is a whole other area of aerodynamics and the shape of the nose can alleviate some associated problems with the pressure wave.

To illustrate.

http://www.jreast.co.jp/e/development/tech/pdf_1/22_28tecrev.pdf

Also, tunnels for high speed trains are designed with vents at the entrance/exit to help diffuse the pressure pulse and stop the noise field spreading too far. In some ways, a train leaving a tunnel is like a bullet leaving a gun with the associated pressure field and blast wave.
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Kiwirob
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 10:34 am

It's not only the Japs with the funky noses

Spanish AVE Class 102

http://upload.wikimedia.org/wikipedia/commons/thumb/8/85/Ave.jpg/800px-Ave.jpg
 
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 1:12 pm

Quoting stealthz (Reply 6):
Certainly is, what is driving this train?

Lots of electricity.

By the way, I could pinpoint the location: http://maps.google.ch/maps?q=couvet+...3&t=h&hnear=Couvet,+Neuenburg&z=19

The route from Bern until Dijon is quite sluggish, and in the countryside, it often looks like in this photo.

Quoting speedygonzales (Reply 5):
Not ICE 1, it only has an emergency coupling for towing.

Thank you!  



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fr8mech
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 2:05 pm

Quoting celestar (Thread starter):
I noticed that in Japan, the Shinkansen, especially the newer model, has very long and slender nose, which in theory, helps aerodynamic but I really wonder if that is true?


I just read an article, in passing that talked about the shape of the nose on high-speed trains in Japan. I wish I can remember which site and/or publication I read it in. It was an article on how engineers mimic nature to solve problems,

The shape of the nose on the newer trains has to do with the pressure pulse formed in a tunnel at high speed and the problems/sensations felt when the train exited the tunnel. With blunt nosed trains, there was a noise through-out the cabin similar to a muffled sonic boom, accompanied by a vibration and a "feeling" of the cabin contracting. All this when the train exited the tunnel. Shaping the nose, mitigated these feelings.
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 2:07 pm

oly720man (Rep 7); thanks for a very informative tutorial. You brought up considerations, though obvious after explanation, I wouldn't have thought initially thought about. Thanks, again.

The zoomy guys pictured in PHX787's Rep 3 look like Luigi Colani was on the design staff! Charlie Jordan (GM Aerotrain of the 1950's designer) would be proud. Very wild indeed, but the unit in kiwirob's Rep 8 does look pretty "frumpy" for sure. best regards...jack
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 2:22 pm

I just read the paper linked by oly720man in reply 7. The article I read was clearly a dumbed down version of this paper, though this paper doesn't talk about the the passenger complaints.
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Francoflier
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 4:04 pm

Quoting stealthz (Reply 6):
Certainly is, what is driving this train?

I'm wondering too.

I can't see a catenary, although I can see poles. It might just be the low pic resolution.

The front pantograph isn't raised either, maybe the one on the aft loco is... Weird, as both are normally raised on non high speed sections.

There used to be a TGV service in western France that went through a non electrified section, on which the trainsets were puilled by specially modified CC72000 diesel locos. But I doubt that was ever used on the Lyria lines, nor in a pusher configuration.

I'm pretty sure no TGV has ever been modified for rail pickup (apart from the Eurotunnel trainsets with thrird rail pickup for the UK portion).
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 4:29 pm

Quoting francoflier (Reply 13):
I can't see a catenary,

there is a wire at about 2 o'clock, along the line of the base of the forest in the background - to the edge of the photo on the right at the same level as the cottage.
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 7:07 pm

I always liked the nose of the Super Nozomi best - it looks like a snake!

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AF1624
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 7:53 pm

Quoting PHX787 (Reply 3):
The Shinkansen recently built is capable of going to 300 kph, and may push it to 320kph later on. The nose was specifically designed to be as aerodynamic as possible.

All due respect, this has nothing to do with the nose.  

The TGV Duplex is rated to speeds of up to 350km/h on certain lines (namely, the Paris to Strasbourg line and the Paris to Marseille line). And it doesn't have a "pretty" nose  
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DocLightning
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 7:55 pm

Quoting celestar (Thread starter):
I noticed that in Japan, the Shinkansen, especially the newer model, has very long and slender nose, which in theory, helps aerodynamic but I really wonder if that is true?

Other issue: when a high-speed train enters a tunnel, there's a sudden shift in air pressure around the tunnel entrance that leads to a phenomenon called "tunnel boom" that is bothersome for people living and working nearby. A longer nose makes the train's entry into the tunnel a bit more gradual and thus reduces tunnel boom.

It isn't all about aerodynamics at speed. The Chinese maglev is relatively blunt-nosed and moves at about 500 km/h, IIRC. But it doesn't have to pass through tunnels.

Quoting oly720man (Reply 7):
Two high speed trains passing each other can generate a huge amount of suction between them at the nose, because of the low pressures there, so having a longer nose helps spread this out a bit and reduce the area of minimum pressure.

I didn't know that. That's pretty cool. The "WHUMP!" from inside the train is pretty impressive when they pass.

Quoting cptkrell (Reply 11):
The zoomy guys pictured in PHX787's Rep 3 look like Luigi Colani was on the design staff! Charlie Jordan (GM Aerotrain of the 1950's designer) would be proud. Very wild indeed, but the unit in kiwirob's Rep 8 does look pretty "frumpy" for sure. best regards...jack

JapanRail basically uses their own brand of trains that are designed specifically for JR by contractors. AFAIK, they are offered outside Japan, but I don't think there have been any takers.

The train in Kiwirob's Rep 8 is a Spanish train by Talgo called the TALGO 350. Spaniards call it the "Pato" ("Duck") for obvious reasons. It's an older model and the main propulsion motors are actually kept in the forward "locomotive." The cars themselves are not powered. While the train was designed for 350 km/h service, its 1000kW motors cannot maintain this speed and so it has an actual limit of 330 km/h. My one passenger experience aboard one only took us to 270 km/h.

The newer AVE and ICE trains are the Seimens VELARO train.


These trains are very popular and have been purchased for Spain's AVE, Germany's ICE, the EuroStar, Russia's new HST (not sure what they call it), and I think the Koreans are looking into it, too. I've traveled on one (my first high-speed rail experience) and it was very passenger-friendly.

The VELARO is an EMU, meaning that each car has independently-powered bogies, rather than a single "locomotive" at the front. This opens the forward and rear cars up to passenger seating at about 60-70% of the capacity of a standard car, allowing more passengers to be loaded onto a train of the same length.
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AF1624
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 7:57 pm

Quoting stealthz (Reply 6):
Certainly is, what is driving this train?
Quoting francoflier (Reply 13):

Actually, it may be hard to believe (I had a hard time believing in it myself when a driver told me) but... nothing.

I'll explain: on certain portions of rails (such as this transition portion), the TGV carries enough speed and inertia to pass it without any power. They call it "circulation sur l'air", litteraly translated it means "circulating on the air".

They use the inertia to clear the transition portion of the circuit, from one electrified portion to another.

They also do this when switching from a voltage to another (usually switching from classic lines to high-speed lines).

When they do this, the driver of the train manually switches the pantographs down then up again in the proper section.

Not doing this when changing voltages, if going from low to high, can actually burn the fuses and immobilise the train.
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 10:28 pm

Quoting francoflier (Reply 13):
I can't see a catenary, although I can see poles. It might just be the low pic resolution.

The front pantograph isn't raised either, maybe the one on the aft loco is... Weird, as both are normally raised on non high speed sections.

There used to be a TGV service in western France that went through a non electrified section, on which the trainsets were puilled by specially modified CC72000 diesel locos. But I doubt that was ever used on the Lyria lines, nor in a pusher configuration.

Actually, the whole route is electrified. And on the most high speed trains I know, only one catenary is raised at a time (German ICE for example). It is beneficial to raise the one at the back end of the train because the slipstream is less turbulent there.

The Val de Travers, as you can see, has serious gradients. No high speed section.  

So the aft catenary must be raised in that image. According to the photographer on the flickr page, the train was in normal ops.

Quoting AF1624 (Reply 18):
Actually, it may be hard to believe (I had a hard time believing in it myself when a driver told me) but... nothing.

I'll explain: on certain portions of rails (such as this transition portion), the TGV carries enough speed and inertia to pass it without any power. They call it "circulation sur l'air", litteraly translated it means "circulating on the air".

They use the inertia to clear the transition portion of the circuit, from one electrified portion to another.

They also do this when switching from a voltage to another (usually switching from classic lines to high-speed lines).

When they do this, the driver of the train manually switches the pantographs down then up again in the proper section.

Not doing this when changing voltages, if going from low to high, can actually burn the fuses and immobilise the train.

"Circulation sur l'air" happens every 10 or so kilometers on normal routes also, because there are "Schutzstrecken" ("protection tracks") between zones that get the electricity from different power stations. These Schutzstrecken are about 200 meters long, and before entering one, the train driver never lowers the catenary - but he switches off the main power. Just lowering the catenary without cutting the power first can do serious damage to the locomotive.

So, the catenary is always up.


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AF1624
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RE: Nose Shape Of A High Speed Train

Tue May 07, 2013 10:58 pm

Quoting flyingturtle (Reply 19):

Wow, that's interesting and it makes a lot more sense. Thanks for clarifying!
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 12:14 am

Quoting AF1624 (Reply 20):

To elaborate on that: These "Schutzstrecken" can be served with power from either side, but this requires radio contact with the control center. This can happen if a train has to stop for technical reasons - just before such a Schutzstrecke, and can't build up enough inertia to pass it.

If the power is cut suddenly (as in lowering the catenary before switching the main circuit breaker, or entering such a Schutzstrecke without switching the main C/B), damage can occur. This is because every electric motor builds up a magnetic field, and that magnetic field will be transformed back into a very high current if the power is suddenly cut off.


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doug_or
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 1:02 am

Quoting PHX787 (Reply 3):
These things can be heavy so they need it to go faster.

Not sure I follow your reasoning

Quoting RussianJet (Reply 15):
I always liked the nose of the Super Nozomi best - it looks like a snake!

agreed
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Aesma
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 2:54 am

Quoting AF1624 (Reply 2):
Then comes another subject which is simply aesthetics. It seems to me that the Shinkansen is one of the prides of Japan and as such, "deserves" to look very futuristic (this is, after all, the nation of robots). If you look at Shinkansen photos, you'll realise that there are a lot more that just one nose style. Whereas if you look at the TGV's, there are about three generations of noses and that's it.

Well the Japanese have strange tastes sometimes, I find most of these noses pretty ugly.

Quoting RussianJet (Reply 15):
I always liked the nose of the Super Nozomi best - it looks like a snake!

Thanks, that one I like.

Quoting AF1624 (Reply 16):
The TGV Duplex is rated to speeds of up to 350km/h on certain lines (namely, the Paris to Strasbourg line and the Paris to Marseille line). And it doesn't have a "pretty" nose

And let's not forget the 574.8 km/h (357.2 mph) record made with that same nose.
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Geezer
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 4:12 am

Quoting oly720man (Reply 7):
Two high speed trains passing each other can generate a huge amount of suction between them at the nose, because of the low pressures there,

I'm very grateful to you for pointing this out, oly; If I'm ever out hiking around the countryside and I come upon a set of "high speed" train tracks, then see that there is a high speed train coming towards me from either direction, I will very definitely NOT attempt to cross the first track, then wait in the "middle" while both trains go "whizzing by" in either direction ! ( I wonder if there has ever been a "dare-devil" who has tried this ? )

Another thing I have always wondered about, every time I see pictures of high speed trains...........does anyone know if one of these things has ever hit a cow crossing the track, while it was clipping along about 350 km/hr ?

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Kiwirob
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 6:20 am

DocLightning = Trainspotter?

Quoting DocLightning (Reply 17):
It's an older model and the main propulsion motors are actually kept in the forward "locomotive."

It's not that old Doc, they went inoperation in 2005, this design was selected by the Saudi's for the Haramain High Speed Rail Project which will link Mecca, Jedda and Medina.
 
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 6:44 am

Quoting Geezer (Reply 24):
Another thing I have always wondered about, every time I see pictures of high speed trains...........does anyone know if one of these things has ever hit a cow crossing the track, while it was clipping along about 350 km/hr ?

I'm not sure if it's happened before, but in my experience the high-speed TGV lines (where they might do such speeds, not on the traditional lines in the picture) are very securely separated from the surrounding countryside so I'd imagine that such a situation would be unlikely.
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speedygonzales
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 7:56 am

Quoting francoflier (Reply 13):
The front pantograph isn't raised either, maybe the one on the aft loco is... Weird, as both are normally raised on non high speed sections.

Switzerland uses 15kV AC on all lines, while southern France use 1.5kV DC on old lines (northern France and all HSLs are 25kV AC), which is why they don't need to use both pantographs in Switzerland.
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Aesma
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 9:48 am

Wild animals have been hit, often boars especially during the week-end when they're being hunted, but it doesn't happen that often since the tracks are protected and there are tunnels for the animals. When it happens it can cause some minor damage to the nose, and the animal is disintegrated.
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PHX787
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 2:22 pm

Quoting RussianJet (Reply 15):
I always liked the nose of the Super Nozomi best - it looks like a snake!

Just for reference they stopped running this type of EMU on Nozomi trains  
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 2:43 pm

Quoting francoflier (Reply 1):
Overall, aerodynamic efficiency is not as important on a train going 300kph than on an airplane going 900kph.

Aerodynamic forces will still be the dominant component of a HST's resistance - in the ballpark of about 90% of the overall resistance. However skin drag will play a much bigger proportion of the train's drag vs an aircraft.

Also an aircraft only typically cruise at about 520kph IAS so the difference is not necessarily that large.
 
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 2:55 pm

Quoting DocLightning (Reply 17):
JapanRail basically uses their own brand of trains that are designed specifically for JR by contractors. AFAIK, they are offered outside Japan, but I don't think there have been any takers.

The HSR trains in Taiwan are adapted from the Shinkansen and built in Japan! But I think this might be the only example.
 
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 3:33 pm

Quoting flyingturtle (Reply 19):
Actually, the whole route is electrified. And on the most high speed trains I know, only one catenary is raised at a time (German ICE for example). It is beneficial to raise the one at the back end of the train because the slipstream is less turbulent there.

The Val de Travers, as you can see, has serious gradients. No high speed section.

Serious gradients needing serious traction, I thought both locos would be on the juice, in which case, at low speed, they prefer to use two pantographs to avoid using the high voltage line that goes across passenger cars. Then again...:

Quoting speedygonzales (Reply 27):
which is why they don't need to use both pantographs in Switzerland.

...I forgot about the 15kV. I don't know how TGV motors and transformers/rectifiers are setup so I don't know how the current pickup is done for every voltage.

Anyhow. I saw the wire. It's no magic after all.
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 4:49 pm

Quoting Geezer (Reply 24):
I will very definitely NOT attempt to cross the first track, then wait in the "middle" while both trains go "whizzing by" in either direction ! ( I wonder if there has ever been a "dare-devil" who has tried this ? )

That "daredevil" would be a candidate for a Darwin award. Most HSR tracks are protected by fences to keep animals and Darwin award candidates off the tracks.
 
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RE: Nose Shape Of A High Speed Train

Wed May 08, 2013 8:32 pm

Quoting Westjet_737 (Reply 31):
The HSR trains in Taiwan are adapted from the Shinkansen and built in Japan!

That's right! I stand corrected.
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celestar
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RE: Nose Shape Of A High Speed Train

Thu May 09, 2013 6:47 am

Wow, I did not expect to see so much response on my thread.
I reside in Taiwan and the HST is indeed a Japanese version. After travelling on numerous Shinkansen and TGV, ICE etc, I like the Shinkansen better because of the cabin's width. The Korean HST is the 'worst' - two of three times, my train were late in departing and arriving with no obvious reasons such as weather or technical! Even the Chinese HST are on time!

Personally, I think the Japanese are taking this into their own mind of pride and beauty and they got very much carried away!
Having said that, all Japanese HST and indeed most of their train are kept so sparkingly clean, I often wonder how much water every day was used in cleaning them! I was at Paris North, waiting for my TGV to Amsterdam for 2 hours, almost 9 of the 10 TGV pulling in looks dirty and worn out. It is a horrible sight. The German ICEIII, IMHO, represents the best of beauty and efficency. The bullet shape front has clean and graceful line. Seeing much of that in some of Chinese version of ICE II now!
 
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RE: Nose Shape Of A High Speed Train

Thu May 09, 2013 7:55 am

A large component of overall drag is the separation forces at the ass end of the train. Modern aircraft and ships (and now 18-wheel trucks to some degree) extend the rear of the vehicle, gradually tapering. You can realize substantial fuel savings with this technique, or merely drag reduction. Look at the America's Cup boats, for example, all have a large fineness number (length to cross-section ratio) and all have gradually tapered sterns. And go like bats out of hell.

When BAC & Aerospatiale did this to Concorde, I think the overall drag reduction was around 3%, which translated into reduced fuel burn, which translated into slightly longer range, I think on the order of about 125nm. GDB would have access to accurate numbers.
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PHX787
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RE: Nose Shape Of A High Speed Train

Thu May 09, 2013 12:25 pm

Quoting celestar (Reply 35):
After travelling on numerous Shinkansen and TGV, ICE etc, I like the Shinkansen better because of the cabin's width.

If the one in Taiwan is one of the export train sets then its the same cabin width. Those trains run on standard gauge tracks too..
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DocLightning
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RE: Nose Shape Of A High Speed Train

Thu May 09, 2013 8:06 pm

Quoting connies4ever (Reply 36):
A large component of overall drag is the separation forces at the ass end of the train.

The trouble is that from a physical point of view, the train doesn't have a front and back. Most trains are designed to be operated bidirectionally so that once the train pulls into the terminus, it can just reverse directions and head back out in the same direction. Thus, each end of the train will be identical.

However, a long and tapered nose on the train will be a long and tapered tail when it is on the rear end, so to some degree, the solution is inherent.
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rwy04lga
Posts: 1976
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RE: Nose Shape Of A High Speed Train

Sat May 11, 2013 2:45 am

Quoting stealthz (Reply 6):
Quoting flyingturtle (Reply 4):
This picture is almost surreal:

Certainly is, what is driving this train?
Quoting flyingturtle (Reply 9):
Lots of electricity.

Of course, but we didn't realize how until it was explained in a later post.

Quoting RussianJet (Reply 15):
I always liked the nose of the Super Nozomi best - it looks like a snake!

I like the 300 series. I have a Kato train set of that series as well as the TGV orange, the TGV blue, and the Eurostar.
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SpaceshipDC10
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RE: Nose Shape Of A High Speed Train

Sun May 12, 2013 4:29 pm

Quoting AF1624 (Reply 18):
I'll explain: on certain portions of rails (such as this transition portion), the TGV carries enough speed and inertia to pass it without any power. They call it "circulation sur l'air", litteraly translated it means "circulating on the air".

Not exactly. They call it circuler or rouler sur l'erre not l'air meaning riding on the way.
 
CPH-R
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RE: Nose Shape Of A High Speed Train

Sun May 12, 2013 6:14 pm

Quoting oly720man (Reply 7):
There are a couple of other factors that come into play with the design of the nose and that is the pressure pulse that is generated as a train passes another object, generally another train going in the opposite direction or a tunnel.

Indeed, allegedly that's one of the reasons why the Danish railways went with a "pointy-nosed" design for their new IC4 class trains, over the old flat-nosed design of the IC3 class. And they're not even particularly fast (top speed of IC3 is 180 kph, top speed of IC4 - whenever they can get the damn things moving - is 200 kph), since we don't really have much high-speed infrastructure.

Of course, this gives the passengers a massive disadvantage. With the old IC3 units, you could walk between each train set until you found a free seat. With the IC4, you have to make a mad dash between units when they're stopped at a station, which is really impractical if you're carrying any sort of luggage.
 
AF1624
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RE: Nose Shape Of A High Speed Train

Fri May 17, 2013 12:45 pm

Quoting SpaceshipDC10 (Reply 40):
Not exactly. They call it circuler or rouler sur l'erre not l'air meaning riding on the way.

Thanks   Makes more sense now.

Also, I have found this documentary which explains in great length a lot of what has been discussed here:

http://www.youtube.com/watch?v=3-ynoTqu3Sk

Really good.
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SpaceshipDC10
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RE: Nose Shape Of A High Speed Train

Sat May 18, 2013 12:51 pm

Quoting AF1624 (Reply 42):
Also, I have found this documentary which explains in great length a lot of what has been discussed here:

http://www.youtube.com/watch?v=3-yno...qu3Sk

That's indeed a very interesting documentary
 
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Scooter01
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RE: Nose Shape Of A High Speed Train

Sun May 19, 2013 3:07 pm

Found some interesting shapes from a design that could have become a high-speed, steam-powered Trans-Siberian express:



For more candy, look here

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