東涌韓制列車外型己經誕生喇!!

[ref=406846]hksubways[/ref]  在 2005-10-29 10:23 PM 發表:



planes are too heavy to fly if they are PRIMARILY made of stainless steel

hmm, first you said no one use it on planes, then you said no one use it primarily on planes...well...

I would still like to remind you that MOST frame of the current planes still use stainless steel, and I don't know if you would consider the frame as one of the PRIMARY factor or not #;D

[ref=406700]hksubways[/ref]  在 2005-10-29 08:11 PM 發表:

Most trains in Europe like to use aluminum alloys while those in US use stainless steel, according to jrtr. alu alloys are lighter hence saves energy but stainless steel gives better protection in collision...

If stainless steel is so good then why no one uses it on planes...

If aluminum alloy (or duralumin) is better than stainless steel why do so many trains still use stainless steel

its cost

First of all, your crappy grammer had make me a hard time to read what you said above.

Next, Al train have enough strength for train crashes like stainless steel.
The material design technology, such as double skin "truss structure" have cleared the problems of strength.

One good example is a derailment of Kyushu occured years before, a tilting express train (A-train series from Hitachi, series 885 of JR Kyushu) derailed upon crashed with a big rock to course it derailed under the speed of 100km/h and no one get hurts badly.
Al double skin structure had proved itself to have enough mechnical charactrics to absort the crashing force and maintaining the shape of the compartment.

Cost is only one of the factor needed to consider when buying new trains.
Weight can be a factor in terms of energy consumption if the train have a pattern of many start and stop operation, but it can also be affected by the drivetrain characteristics.

[ Last edited by 500 on 2005-10-29 at 23:16 ]

[ref=406702]hksubways[/ref]  在 2005-10-29 08:16 PM 發表:

Furthermore the VVVF system on K-trains emit a very loud noise which not many people could tolerate (at first) and of course the really loud a/c noise emitted from the train's exterior

首先我要就閣下的用詞作出釐清:
1) very loud noise, 究竟有幾 "very loud"? 你有冇度過周圍既環境噪音?
已知人耳會因應環境噪音調節靈敏度, 咁係幾多環境噪音中以乜聲
波頻率下幾多分貝先係嘈? 幾多分貝先叫可以接受?幾多分貝先叫靜?
2) not many people could tolerate, 有幾多乘客不能忍受? 係用演繹法定
歸納法推論出黎? 中間有冇取樣不足、結構偏差、有已知失漏既問題?
如果有是但一樣的話, 就犯了以偏概全既謬誤
3) really loud a/c noise , 上文已有提及類似問題, 不贅

總括而言, 由於閣下所提及標準語意性質過於曖味, 建議先提出理據
及數據以避免言詞之爭, 畢竟沒有意思的文字連真假也提不上

[ Last edited by 833637 on 2005-10-29 at 23:45 ]

[ref=406928]hksubways[/ref]  在 2005-10-29 11:31 PM 發表:

Let me clarify a few pts here

1. The point of me stressing "planes are primarily made of stainless steel: they won't fly" is to stress the point of cost vs weight factor. Stainless steel is cheaper but heavier, hence more expensive in the long run

2. Plane manufacture, in recent trend, has pivoted from mainly Al frame construction to carbon, best exemplified by B787

3. Al alloy, though more vulnerable during crash, would be fitted, like any other vehicles, crumple zones and crash protection. I don't have the figures, so I ain't sure, but JRTR magazine did say that stainless steel is safer during crash.

飛機設計與鐵道車輛設計係兩回事，由於呢度只對鐵道設計及其材料作出討論。
故此我必須無視有關飛機設計部份以便討論。

鐵道車輛係設計時的要點為：裝做工序、重量、強度、維修、價格、共通等。

不鏽鋼與鋁合金的工法上根本係唔同，好似不鏽鋼由骨組方式轉為面裡材接合，
同鋁合金由單層外殼到雙層蜂巢夾層，再到由大型中空押出材加以對接的雙層外
殼，其工序已經係兩個世界，更唔好提有關強度。

不鏽鋼的長處係原料加工性及sourcing比中空材快同簡單，而鋁合金的uniform設
計係接合、內裝加工性方面比不鏽鋼好。

重量方面由於宜家盛行的超輕量化設計，不鏽鋼車可以做到26-28噸，而鋁合金車
同樣設計則要34噸以內。(以日本20m標準仕樣通勤車為例，車輛強度相等)
但使用壽命、最高行車速度的設計則有所不同。

JRTR的料係有參考價格，不過佢的資料並不是最update的，以其做源點還可以。
而就平交道事故，各鐵路公司早已對有關cab的設計進行大量改良。

不鏽鋼車對鋁合金車的sales比例由以前的不鏽鋼慢慢移向鋁合金的其中一個原因係
為o左將維修工序簡化。

緊記鐵道車輛的做法根本係冇一個定案(model answer)的。
同埋，你地話我崇日都好，日本係做車技術(車身、驅動系統、使用簡易度)上的確比
歐洲行先好多年。

4. Please accept my apologies for my "crappy grammar". I think you need to differentiate crappy grammar from colloquial English. I wrote my msgs in a hurry (all written in one minute) and of coz the extensive use of shorthands and abbreviations... I think you need not lecture me on how to use my English, and besides I don't think my English, albeit dotted with colloquial language that may "look foreign to you" because of your previous nonexposure, here and there, would render my passage equivocal or ambiguous.

你有乜野理由會推斷我會教人做野呢？
你的口語英語的確係睇死人，係討論區唔係要有效與人交流嗎？#:-[

[ref=407124]hksubways[/ref]  在 2005-10-30 01:54 AM 發表:
I think its very well known that the VVVF system emits a rather loud and noticeable noise when the train accelerates up to the certain point, when you are standing above the motor. Now compare it with the noise on that SP 1900...

相信你所指的 "a rather loud and noticeable loud noise" 是指：
當K-Train 加速至約 30km/h時，摩打所產生的一個響聲，在日本稱之為「爆音」：
片段的第12.5秒
片段的第42秒至1分11秒

只要是採用三菱2-Level VVVF素子及調頻程式的列車，摩打都會在某個速度時
發出「爆音」。K-Train約在30km/h時產生、SP-1900列車約在37km/h時產生。

當K-Train或SP-1900列車在摩打出現「爆音」的速度時，採用較低的加速率，
列車便會長時間維持在該速度，令「爆音」出現的時間較長，而令列車出現
震動及引入頗大的噪音。無論是K-Train還是SP-1900列車，都會出現這個問題。

at first when the trains were first introduced... if you have noticed the
faces or rx of many pax near that area, you would know what I mean. If you
don't recall then I really can't help it, sorry.

沒錯，在K-Train運行初期（即還未採用ATO行車時），因為個別車長在列車
運行至30km/h時，採用較低的加速率行車，而導致「爆音」非常大聲及冗長。

不過自從K-Train採用ATO後，列車在30km/h時通常採用較高的加速率行車，
所以現在已經沒有這個大問題。

我亦不認為因為「爆音」問題（即你所指的"K-trains emit a very loud noise which
not many people could tolerate"），地鐵就不應購入設計相若的東涌線新列車。

[ref=406702]hksubways[/ref]  在 2005/10/29 08:16 PM 發表:
we all know that the traction system on K-trains, when the trains were first introduced, had huge problems with very abrupt accelartion, I think everyone knows that, the braking system were just as bad... this was before the systems were finetuned subsequently...

韓國列車其實在不少方面均有改善，但制動方面仍然有不少問題。
最大的制動問題在於繁忙時間，列車和列車的距離太接近，很多時K-train輕力制動中間會忽然來一次大力Brake，但大力Brake之後又會很快放開，令人防不勝防，但舊車卻沒有這種問題。

另一個問題是車門的開關仍然要加以調校，開門彈出的一下，可以慢一點，而關門上鎖的一下，可以調校得如A301/A302的速度，因為部份K-train的上鎖要鎖幾2才鎖到，亦有上鎖時發出太大的巨響(估計是鎖不太配合門的關上時間)

最後一個問題是本人觀察而來的(不肯定是不是問題)，就是K-train的車身高度，好像比M-train多變。同一站同一月台位置，M-train的高度大致相等，但K-train有部份好像沉了下去。