ctxmf74 wrote:
>
> --- In [email protected] <mailto:S-Scale%40yahoogroups.com>,
> "ecphora123" <[EMAIL PROTECTED]> wrote:
> >
> > A 2% grade (or any other percentage)is easily measured and
> > constructed in a straight track situation, but just how does one
> > accomplish the same on a curve? how do you draw a track plan for a
> 2% grade
> > on a curve, knowing that each point on the curve is at a 2% increase?
>
> The larger you draw the plans the easier it is to scale the length
> around curves. I like to use 1/2 inch = 1 foot as a minimum and
> prefer 1 inch or 1.5 inch if possible. The rise and run formula works
> for scale or full size. If you can find a flexible ruler it's fairly
> easy to measure length following the curve centerline and then
> calculate the grade at any point along the way. A calculator can give
> the length of curves if they are 90 degrees or 180 degrees(or any
> amount if you can measure the central delta angle). I've never tried
> the common model railroad layout design software programs but they
> should contain some kind of circular arc calculations for length and
> grades?
> Real railroads keep track of grade and distance by using "stations".
> from a given starting point defined as 0+00 if they go 100 feet along
> the line it is called station 1+00. one hundred more is station 2+00,
> another 150 feet would be 3+50, another 6 inches would be 3+50.50,
> one mile from starting point would be 52+80, etc. Each station has a
> grade determined by the design profile. The stations continue around
> curves measured on the centerline of the track. The grade between any
> two stations can be calculated by rise and run.
> I've stationed plans for layouts with complicated grades. It can be
> done in inches from starting point or in scale feet, the elevation
> units have to match the length units, (scale feet or actual inches).
> Once the layout is stationed it's easy to calculate the finish grade
> at any given spot and to get riser heights above the existing table or
> framing, the real railroads call these heights cuts or fills, cuts if
> the finish grade is below the existing and fills if the finish grade
> is above the existing......dave
>
>
Hi all:
I have found that using a good string (type used in building a block
wall to make sure it is level). I measure off 1 foot lengths on the
string, lay the string down the center of the track (straight and curved
sections), determine how long the track is, how high I want to go for
clearance, and then use the (rise/run)x100 to give me the percent
grade. I also have one of those adjustable levels that were for sale -
they tend to work pretty well as I adjust the risers to give the
appropriate height. Using the measurements in the first part, you can
also do some calculations and establish how high each riser should be
depending on how far it is from the 0" level to establish a given
grade. Lots of ways to do it. (and some even work :-) )
Rance Velapoldi (Norway)
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