Re: [NSW] Cityrail Grades

["Paul Jones" <jonesclan@free.net.au>]

So if dy/dx is the gradient at a given point, what's y equal to??

____
Paul Jones

Ben Armstrong wrote in message ...
>On Wed, 12 Apr 2000, Anita Lukaszyk wrote:
>
>> I *think* it uses 'feet' instead of metres.
>
>It doesn't matter what units you use. It's the ratio that's the
>important bit.
>
>> Please dont use TAN. It reminds me too much of Year 10 maths!  :) That
bloody SOHCAHTOA thing...
>> AAAARGH!
>
>Have to agree with you there!
>
>> Hubert Lam wrote:
>>
>> > Sorry does "1 in 40" mean tan x = 1/40 (rises 1 metre vertically for
every 40 metres of horizontal
>> > track) or does it have some other meaning?
>
>Yeah- Rise over Run.(you see- geograpghy is useful!) I'm not sure
>whether they would use sine instead of tan though. (top bit of the
>triangle) Wouldn't be that much difference anyway.
>
>Another thing that has to be taken into account when talking grades is
>whether the grade quoted is compensated for track curvature or not.
>
>Say that a bit of curved track is said to have a 1 in 30 compensated
>grade on it. The track itself may only have a grade of say 1 in 35, but
>it is 'rated' at 1 in 30 to allow for the extra rolling resistance
>through the corner. (so that enough HP is put at the front of the train
>to get everyone home happily) :-)
>
>Hope this helps,
>
>---
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