Train is an open source build script engine based on JavaScript. It is not tied to or specific to Elements (although it is written in Oxygene, but it is used internally by FXGen and HeaderImporter.

If you use the FXGen GUI app, it comes with Train embedded, and you don't need to care or read any further. But if you want to use the HeaderImporter command line tool, you will want to build/install Train and use it to script HeaderImporter, as described in the HeaderImporter topic.

Train uses JavaScript as its scripting language, extended with a range of APIs that are useful for creating builds scripts, and we recommend considering it for your own build automation purposes as well.

Train is open source under the BSD license, and available on GitHub via