My Roundhouse isn't present one but as engine shed in 1847, which has ash pits, narrow tunnels, and circular supply channel (I guess).
I will make the entrance, rails, a turntable.
My system are as follows.
Mac OS 10.14.6
FreeCAD ver.0.18
A tool I use mainly is Part workbench, I don't know how to use other tools well.
I want to master more skills for time to pass in the pandemic.
Stay Home, Stay Safe, and Stay Positive!