Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

High-speed vs conventional train

[Subject Prev][Subject Next][Thread Prev][Thread Next]
When you ride a HST, the feeling is similar to that being on a plane,
but with different ups and downs.
Now, to nit-pick (right spelling?) on the opinion below.
Work is force multiplied by a distance travelled.
The multiplier of 27 is on the force. The distance covered, in a unit of time, is 3x larger,
so the energy needed is 9x larger.
But the aero resistance is only a part of the total, so energy input will not grow that much.
Also, the aero shaping is better, which further descreases the multiplier.
The frequency-of-use factor will divide the result by 3.
Gregory from Oz
On Fri, Oct 29, 2010 at 11:53 AM, IRV FRUCHTMAN <ifaeng(--nospam--at)> wrote:

>   Fellow Engineers,
> High speed trains are wonderful engineering feats, but I don't believe
> saving energy is one of them. As I recall from my school days: drag force=
> proportional to speed squared and power (read energy) is proportional to
> speed cubed. Therefore a train moving at 300 mph, compared to a train at =
> mph,  uses (300/100)^3 =3D 27 times as much energy.  If the requirement f=
> the number of trains is reduced by 1/3 =96 to move the same number of peo=
ple -
> then the increased energy use is 27/3 =3D 9. Therefore, 9 times as much e=
> is required to move the same people/ load with a high speed train as
> compared to "low" speed train.
> Given a choice, I'll take an airplane.