Over the years I've used belts, timing belts (what Sunset 3rd Rail uses), chain, gears, shoot you name it, I've tried it. Timing belts are a great resource for some applications. I use a lot of them on my diesel drives. I also use NWSL when I need a new gear box on a steam engine model. Always ball bearings
Stock Drive Products (SDP) is one of the primary resources I use for timing belts and pulleys (I also use McMaster-Carr). They have a great tool for computing ratios, length of belts, spacing, etc. It is a tool I use all the time. I will attempt to post a link.
https://sdp-si.com/eStore/CenterDistanceDesigner
I use mxl and I thought Sunset did also but I was wrong. They use 40 D.P. They look close but are not the same. I know this from experience.
