Has anyone had any experience in using chip dust for ballast???

I am curious as it seems to be available at most gravel yards for fairly decent prices

Also, anyone know of a supplier of small quantities of coal?

thanks in advance,

Ok, earlier I made a post about using ez-track or flex track.  I received a lot of great feed back... thanks again.  So today I decided to use the ez-track, that I have on hand, and set it up under the Christmas tree for my grandson so he can have some fun before i start the formal bench top lay-out.

Time and again I continue to see photo after photo of brand new continuous welded rail in pre 70s model railroading. If you just scenic the photo side of the rail with rail joint bars every 39 ft. it really picks up the realism of the scene. It surely does nothing to sell the scene when it's 1951 and all rail is welded rail. The Santa Fe line running along I-25 in Northern NM. is perfect for setting the scene. Jointed rail and semaphore signals. See it now or miss the last of 1900s railroading.   

What should be minimun radius of curve for a N scale layout?

and should be the best? let say a middle point between space and not to look too much as toy train?