I haven't requested the RollingCarts plugin yet because I don't see any config.yml file or any instructions on how to install the plugin. I have to describe how you install it when I request it.
And if you have to configure anything like the speed of minecarts (which I think I'll keep, at least to start with), I'll need a config.yml file. I couldn't find any download link to that one, only a download link to the pure .jar file.