Calculating Tie Lengths
in a Complex Wye Switch
In a Wye, both routes diverge in opposite directions.
As the routes separate, the ties need to get longer to accomodate
both tracks until they are far enough apart to have their own ties.
Sometimes one route is straight for some distance beyond the points,
but begins to diverge while ties are still common between the two
routes. This is a "Complex Wye".
Sometimes the turning radius of both routes are the same. Other times
they are different. In this model, all ties are parallel.
This program calculates the lengths of the ties needed to complete a
Complex Wye switch. It will also calculate the frog angle and number
based on track gauge.
Explanation of Input Boxes
Note: All dimensional units must be the same. Inches, meters, etc.
Radius of First Branch and Radius of Last Branch
The first branch begins diverging immediately at the points, but the
second branch continues straight and then begins diverging in the
opposite direction a fixed distance from the points.
There are two boxes for the radius of each branch. One box for the
measured curve radius and one for an optional multiplier which can
be used for unit conversion (such as feet to inches). If not needed,
the multiplier should be set to 1.
Distance to Second Branch
The Distance to the Second Branch is measured from the points.
Normal Tie Length
The length of a normal track tie. Switch ties will progressively
get longer.
Tie Spacing
The measurement from tie to tie, not the gap between them. It is the
center to center distance. The width of ties is not needed.
Snap to Nearest Unit
This allows you to select how much precision you need. The tie length
will be rounded to the nearest unit you select here.
Track Gauge
This is only needed if you are using the optional frog angle and number
calculator. Enter the actual gauge-face dimension. The frog angle will
be calculated in degrees. The frog number is 1/2 the cotangent of 1/2
the frog angle. Both frog angle and number are rounded to .25.
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