IIRC "engines" were never built into rails (before 3.0). I believe you were referring to this plugin: https://github.com/lazyatom/engines https://github.com/laz

IIRC "engines" were never built into rails (before 3.0). I believe you were referring to this plugin: https://github.com/lazyatom/engines https://github.com/lazyatom/engines. Honestly, before rails 3, the whole plugin initialization process was a mess. Things are a lot better now. Props to yehuda katz for great work on refactoring on rails 3. What's wrong with cutting backwards compatibility with old apis after a while? The core team does provide deprecation warnings when they plan on changing stuff, so it's not a complete surprise.