Re: Implications of ICE crash

[ssel@actrix.gen.nz (George Jones)]

On Tue, 9 Jun 1998 21:27:17 +1000, "Paul Jones"
<dj_nightshade@geocities.com> wrote:

>hmmm let's see.
>180,000kg's of train
>55.55... metres per second
>2300 metres in wich to stop
>but how much force is applied by the brakes? (in newtons)
>i'll assume a decceleration of .5m/s (can someone tell me that too?)
>...
>...
>= 166 seconds??
>guess i need more info...
>
>--
>Paul Jones

>>Hmmm. Say, 180 tons of train (Leading power car and trailer) travelling
>>at 200 km/h. I wouldn't be too surprised if someone were to do the sums
>>and come up with a stopping distance of 2300 metres.

Kaitiaki records in NZ (black box/vigilance enhancement product I had
a hand in building) show about 2.5 to 3.5 kph/s deceleration in
emergency braking conditions. eg 27 s to stop from 93 kph at
Koromiko's fatal - 3.4.

Taking 2.5, then it takes 200/2.5 = 80 seconds to stop.
s = 0.5 a t t
   = 0.5 x (2.5 / 3.6) x 80 x 80 = 2222 m.

So it is reasonabe to assume that the front units were in emergency
braking, triggered by the break in the train, at a lighter
deceleration than in conventional trains.  I would be surprised if the
driver did not notice.  I assume that there is a black box recorder
that has logged all this.

George Jones