Plywood

I personally think it would sag if used for structure, and if you're looking for sound deadening, Homasote will do a better job.

It is just a train board.  If you like it and want to work with go for it.  Just about any kind of flat board will do.  Even tongue and groove 1x4, you name it.  Just so it is strong, flat, no stink and no bugs.

I use bagasse board made from sugar cane pulp in Jamaica and then 1/2 inch cheap plywood in USA.  Both work and are what I could find.

Charlie

From Constant Spring, Jamaica

If the panel has any structural value as a 1/2" roof or flooring product, the sheet should bare a stamp of "32/16"...in the plywood industry, the stamp indicates the product can be applied 32" on center on roof and / or 16" on center as part of a floor system.  I'm not familiar with the product you mention, but if it's wood components or core is southern yellow pine, be aware that some warping may occur in high moisture areas such as a basement, or as we say here, the train room

I saw that stuff in the store and it had a strong asphalt smell to it. Not sure if it would eventually go away or not.

I use it on top of plywood to kill sound. The asphalt smell goes away quickly but be prepared to use a ton of paint on it since its essentially a thick piece of cardboard.

On the job site it is referred to as intermediate sheeting. We are seeing it more often because of the high price of the better alternative.  It has very little structural value.  When used as wall sheeting you can push your hand through it with very little effort. It can be purchased with the asphalt on one side or both sides. It will not hold screws as well as Homasote but if you are planning to use ballast to hold your track in place it will suffice. Like Homasote it must be placed over some sort of structural sheeting. You can walk into a garage that was sheeted with this product and still smell the asphalt after six months so I would suggest sealing it on all sides with either Bulls eye or kilz oil based sealer.   I am not sure why we are always trying to reinvent the wheel, we have a perfectly good product that holds screws well, doesn’t smell, is available at Menards or most lumber yards and yet we are always looking for an alternative.  I would not recommend it, but if Homasote is not available in your area or you are on an extremely tight budget it will work.  

Just wonder if it was any good.  Saw at Lowes or Homedepot can’t remember.  I use Homasote from Menards.  Thanks guys.

I'll stick to Homasote, that stuff sounds pretty toxic.

Menard's in your are carries Homasote.

7/16" OSB is back down to more reasonable levels- $20/ sheet. Not cheap, but no smell, holds screws ok, can easily the weight of O gauge trains or most people stepping on the layout, if you use 2x4s underneath them.

Yes Menards has homasote in St Charles Mo.   Thanks to everyone who commented.  Just saw how cheap it was at $19.00 at Homedepot.