So the question at the end of the video … Do the 031 switches need to be changed also?
My thoughts are that it depends on what the switches are being used for. I couldn’t tell from the video if they were dead end sidings or were passing sidings accessible from both ends.
You can mix and match different size curves around the layout with whatever switches you want. Any engine can go through the straight section of any size switch. The issues come up when you try to run a larger engine through the curve of a smaller switches. If you have dead end sidings in which you only back a train in and disconnect, 031 switches probably won’t be an issue. But if they are passing sightings and you want larger engines to maneuver in and out of the curve sections, you should probably go with a larger switch.
For what it’s worth, as I‘m planning my next layout I’ll have a combination of different sized curves and switches. My main line will be larger curves with 072 switches and that’s where I will exclusively run larger engines. But on my branch line and industry sidings, I will have smaller curves and switches where I only intend to run switching engines and other smaller engine types.
