This track looked very similar to standard S gauge, except it had one nail hole in the center of the tie, rather than two nail holes on the  tie the outside of each rail.  HO catalog illustrations use photos of the S gauge track, as the two holes can be easily seen.  This track was promoted as making model railroading possible on a standard card table.  The track formed a circle that measured 28 1/2 inches in diameter, It was offered concurrently with the standard Bakelite base track that had been offered since 1947 which formed a 32 inch diameter circle.