It's code 80, and is compatible with other code 80 track like Atlas snap track and flextrack. You just need to remove the unijoiner (use the little blue 'guitar pick' that Kato includes with their rerailing ramp to easily take it off) and use the regular Atlas joiners to attach the 2 together.
I have had my Unitrak layout double mainline with several switches and sidings, a branch line with stubs for over 6 years permanently attached to my base, and now permanent groundcover will begin. i used Unitrak because it was infinitely more reliable than anything else, and I did not want to spend my running sessions constantly getting up from my comfortable tilt and swivel to fix an unscheduled derail, uncouple, or car problem. Yes I have some derails but the track is not the cause - usually something from my train falls on the track - horns, springs, coupler parts, etc, which cause the problems. Although I clean it regularly, I can deal with these very non-frequent mishaps, compared to the flextrack layout (very carefully laid) which was inconsistent in its performance due to weather and layout room temperature. Ken "FloridaBoy" Willaman
