Hello!
I was about to setup a make-shift track on a 20"x48" surface. I grabbed my old HO tracks and was quick to discover that I couldn’t make a full turn with just 20" lol. So I was going to get my N-Scale tracks out and try that but I can’t find them anywhere!! =(
So my question is: Is it possible to build a turn on 20" using N-Scale tracks to the point where the train will be able to corner it safely?
Thanks in advance for any replies =)
Just barely. The minimum radius you can get in N (without using flextrack) is 9 and 3/4". That means a loop is 19 1/2" across. But that’s the track centerline, so your ties might hang over the edge of your 20" table. Probably not a great idea. Sorry!
Unless you go with traction, and then I’ve seen down to a 7 inch radius, but thats tight.
While you can’t make an oval, you can make a nice switching layout in that space! 
cf7
you can always go into z scale
Or Nn3!
If you use flextrack, you can bring the radius down to 8 1/2". Kato is the only manufacturer I know of that makes 8 1/2" radius curves in N scale. Other manufacturers don’t make it this small do to limitations in what equipment will work on curves that small. You will be limited to smaller equipment such as switchers, geeps, and 40 foot cars. My druthers would be to ditch your 20 x 48 board with a 24 x 48 handi panel from a home center. If your 20 x 48 board is framed, you could nail the handi panel over it giving you a 2" cantilever on each side which is hardly anything.
You want the track at least 2" from the edge. You could get by with 20" IF you can insure nothing will fall to the floor. Take a look at the Thomas train tables. They add a sheet of plywood 1" to 2" to the edge above the surface. You may be able to get a 1-2" wide sheet of Masonite to work as a edge guard/safety strip to make the layout “look” better. The best solution is to widen your board to at least 24" or more.
In this environment, you can run short 4axle diesels & 40ft freight cars. The trolleys & PCC cars made by Bachmann or MP are very poor runners. Your best bet for track would be to use Kato plastic Unitrak. You could use Bachmann EZtrak if you don’t use any turnouts. LL plastic track is also very poor.