Custom Charts

There's a chart editor called MercuryMapper.

Check out the MercuryMapper Tutorial to learn how to chart!

There also exists a browser-based chart visualizer called MercuryPlayer, which can be used to view charts without opening them up in an editor. A nice way to preview charts made by others. The version linked specifically has support for previewing charts on a cab, if you so desire for whatever reason. It also has all the charts in the base game available to preview, without audio.