I have just released a video about ball bearings for LEGO trains and compatible. Ball bearings make your trains faster, you consume less battery, and you can pass through tight curves with less problems.
The video describes what material you need, how to fit the ball bearings into your wheel sets and what the effect is.
As always, the video ends with some train operation scenes from a recent layout.
We have also created a web page about ball bearings on https://mattzobricks.com.