Here is a lot of 5 pieces of Lionel track 6-12925. This is the full O gauge black tie tubular track, but it is a WIDER diameter for your circle. Instead of a 31 inch circle, the 042 makes a 42" circle.
It takes 12 sections to make a COMPLETE 42" circle, so these five are one short of half a circle. It matches up to the most common, traditional sized O gauge track in Lionel sets past and present (until FastTrack), USUALLY the track with black ties. It does not match up (height wise) to the smaller 027 type track, usually with brown ties. If you have questions about this, just send me a message!
CONDITION: C-7. These have been used, but they still look good. All pins. Clean tops. Some oxidation on sides.