I copied this info previously from the forum for using as a general guideline.
[The ties that I used on my track are 1/4 x 1/4 square stock wood in 36" lengths cut to 2 3/8" long and stained. It took a long time but the result was good.
The Ties are 1/2 x 1/4 Bass Wood cut to 2-1/4 inch length. Painted Flat Black. Place wood ties under rails, 3 ties between Lionel metal ties. Add ballast, then held in place with white glue / water mix.]
I bought my wood at Home Depot and I believe it was 36" long. One side was flat and the other side was rounded. I painted (not stained) the strips before cutting and then painted the ends. Here's a photo of what I did.
Charlie