If you are using Lionel (or equivalent) tubular track, you can make them, or (I think) you can buy wooden, plastic, or rubber ones that mimic the steel ones. Notice that the steel ties on O27-height track, and O31-height track are different. By creating wooden ties that mimic either of those two profiles, you can make "pretty-good" looking tracks, but they still have that toy-like appearance. That can be a good thing, if toy-like is your layout motif. Real ties on mainlines measure 7" x 9" x 102" on 21" centers. The wooden Lionel-ish ties that I am suggesting will not comply with those dimensions, of course.
All the other major track systems come with wood or plastic almost-scale ties. GarGraves wooden ties look nice, but are a little over-sized. That is a function of their flexible track geometry. Any smaller, and they would probably split when being manipulated. The other sectional types have ties that are more to scale.
When I was a kid, a kindly old carpenter made me a few hundred almost scale wooden ones, which I stained black, and inserted into my Lionel O27 track system. By filling in between the steel ties, they created an illusion that they were the only ones (well, a kid's illusion). It looked pretty good to a 10-year old.
