layout minimum size

I would think the same size could be used for an 0-31 oval with a spur.

I don't have the MTH track library but it would be about the same as this. 36"x54" gives reasonable clearance around the edges. You could maybe squeeze it down to 32" width as an absolute minimum.

 

If you can spare 36"x 60", consider this variation with some O72 curves for easements. The train will flow through the curves more smoothly and with a better appearance.

If you wanted to shorten these, the straight tracks are each 10" long.

27 and 31 are the overall diameters of the curves.

thanks.  that looks like it will work just fine.  I have an old rail king blue comet that I no longer run that I could give him.  When I built the HO scale this weekend, each child helped me paint the tan for the ground and my oldest boy helped hold the wood while I screwed the support boards on the bottom.  My 3 year old kept jumping for joy at the building process.  I want to give my 7 year old a HO layout with an unused KSU engine and some flat cars with tanks and men and army box cars that I have had for a while.  My 3 year old loves trains more than anyone and will not leave the track in the spare room that is for the Christmas train alone.  I think I will build a third and put snow on it and put my HO Marklin I bought in West Germany for my wife's table village for Christmas

If at all possible, stepping up to 42" diameter curves will give a much better result than 27, 31, or 36 inch diameter curves.  Can you get away with a 4 x 8 sheet of plywood? 

 

Also, if you have the room, you can find 60 inch wide plywood which would allow you to step up to 54 inch diameter curves.  The curves will look/work better and you will be able to use a lot more locomotives down the road....if that matters.

A Point I would make.

O-31 is 31" from center rail to center rail.  The outside edge of the track is a couple inches larger.

I would make the table 36"X 54" minimum for an O-31 oval w 20" of straight on each side. This gives you a couple inches outside the track all around.

For the version with easements will just fit on a 36" X 60" table but have barely an inch all around.

I am trying to keep it small enough for my son to be able to hide under his bed and bring out later on his own so i am trying to keep it to five ft. i built a second table four feet by five so 42 inch should fit right?

As an alternative to storing a minimum-size layout under a bed, you may want to consider my recent project with a long narrow shelf along a bedroom wall which fits over existing furniture.  

 

https://ogrforum.com/d...nt/10440673242762760  

 

It's kinda high for children, but they can use a step-stool to access it. Best of all, you don't have to put everything away to stow it under a bed, so it is more available for fun on short notice.  

 

My original plan was to built a shelf 32" wide so I could do a shelf up to 12 feet long with one 4x8 panel (cut into three 32"x 48" pieces which are arranged end to end). The overhead shelving is very useful and the entire structure has no attachments into the walls, the way I built it. It can all be easily disassembled if necessary. The sharp O27 curves are moderated with wider-radius easements, with the track plans I devised. Or you can fit O31 curves onto a 36" wide shelf.  

 

Just another possibility for you to consider.

Thanks all.  I still am not sure, I think I want to stick with a small table since I already have seveal big tables, 4x12 for HO and 5 x 16 for O.  and today I am even less sure though since we caught him playing with matches under several trees thinking he was survivorman.  he may not have christmas this year at the rate he is going. 

Here's a bunch using MTH track:

 

http://thortrains.net/marx/35mth1.html

 

http://thortrains.net/marx/35mth2.html

 

--Greg

I'd tell him Survivorman wouldn't use matches. 

 

Good luck!

 

--Greg