how to calculate the radius of the railroad line?

I want to calculate the radius of the railroad lines which are constructed by multiple polylines. but it seems that ArcGIS only provide tool to calculate radius for simple curve.

Should I approximate the polyline to curve? anyone has some ideas? thx in advance.

Do you want to calculate the radius yourself? You need only three points. Google for ‘calculate radius of circle given three points’.

Or do you want ArcGIS to do it for you?

Multiple polylines? One polyline of three points would do. Please give an example.

Can’t you draw the curve and just measure the radius?

thx for ur reply.

In my case, I have to determine all the radii along the railway line which is constructed by hundreds of polyline. Some of the polyline may contain multiple curves so that using only three points would lose so many radii information.

Is there any geoprocessing tools for it? Or I have to use some other cad software?

the railway line looks like this
FluxBB bbcode test