MinecartRevolutionTags is a plugin for MinecartRevolution which adds the TrainCarts tag system to the main plugin. You can add tags to minecarts and check them later. They are stored in /plugins/MinecartRevolution/plugins/MinecartRevolutionTags/tags.properties. You can get the plugin from BukkitDev. If you have found some bugs please create a ticket on the BukkitDev site.
You can find the source code and contribute to the source repository on GitHub.
Installation
Firstly, install MinecartRevolution itself. Then place the MinecartRevolutionTags JAR in your plugins folder and restart the server. No other configuration is needed.
Documentation
Documentation can be found on the BukkitDev page.