Since routes in engine are isolated by default from main application so that you can have the same routes without clashing using default route helpers like
about_path from main app will result in an error when you try to load it from inside the engine or access engine root from main app.
To fix that issue assuming you have an engine mounted:
Blorgh::Engine.routes.draw do resources :articles end
to enforce using engine roots you need to change
blorgh.about_path and to enforce using main application routes you need to change it to