PHP is not equivalent to Rails. It would be more accurate to compare PHP to Ruby and compare Rails to a PHP framework like Kohana.
I've worked with both Kohana and Rails. Rails is more popular so it is easier to find solutions and add-ons. However, it does a lot of things by 'magic' and a beginner will have a hard time modifying rails source or creating a gem (if they want to do something non-default). Kohana on the other hand is easier to understand, extend, and modify, because the entire source is in your project folder as PHP code.