Balls fall right through red gears

[chrisjj]

Actually, behind them.

E.g. https://jessecrossen.github.io/ttsim/#s=13,17&z=48&cc=7.5&cr=8.5&t=1&pt=8&sp=1&sc=0&b=data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA0AAAASCAYAAACAa1QyAAAAAXNSR0IArs4c6QAAAPBJREFUOE+1kzEOwiAUhh+Lc0dHOIMHaAcP0gbvUS5C0t7DgdHJeAMYnYwnKPraggivcZKkSfn5P35e+2DGmKltW8BnGAZomgaMMRBGriulgAUITdY6EIJHILxo7UDKRScgy4JRCOGt/Z4XUGooolYBN4pJdV0vCWwN8v7DoZbMx3H0c00RCmAKZRoNUWBygt9QMONGa/o2FCrK6kH5TxDx7X8nbUFKqSlf6/s+dkbXdclPW5yMc15A1lkQXIB2GiSXRV4BpV1NtROuk0kBpCC8PiSEZgSpgfdt7sYTP8C1esDueYR7dYb9zcFlq9Xf+gs7cqew2FcrKgAAAABJRU5ErkJggg==

This in latest Google Chrome on Windows.

[Grape-Boy]

pretty sure that's intended

[VuiMuich]

Yes, red gears are just passive linking elements and don't interact with the marbles.