I picked up on that trick from Boone Morrison, who writes articles for the Narrow Gauge and Shortline Gazette.
You can also run a regular piece of thread through beeswax to control the fuzz, , that is what ship modelers have done for years to make their rigging look better.
This stuff I got from Handcock fabrics, and it is Button and Carpet thread, and as you can see from the photo, it looks quite good.
I also have some actual steel cable, which I got at the Bass Pro Shop. It is sold in bulk for fishermen who want to make their own line leaders. You can buy scale cable from some model companies, but it is much more expensive.
The cable though, requires a considerable tension to look right, I have used it as guy wires for a spar tree, but It would be extremely difficult to get it to wind around the drums, or make the turn in a pulley convincingly.
On my big donkey at Terrapin. the drums are wound with carpet thread, but the thread running off to the high line is not attached to the donkey, it lays across the top of the drums, passes through a hole in the floor, through a hole in the layout, and a big fishing sinker hanging under the layout keeps the line taught through heat had humidity variations.
Also when clumsy fingers snag the high line while trying to rerail a log car, or install a log load at the landing, nothing is damaged. I had wanted to do something similar with the surry parkers, but the elevated platform, with the need to roll cars under it made the implementation unworkably complicated, I might thry setting up a sinker at the other end of the cable
Bill Nelson