After installing Phusion Passenger (also known as mod_rails)  and creating a Rails application to test the environment, I was able to view the default “Welcome aboard” page that is displayed on new apps, but got an error after clicking the “About your application’s environment“. This was the message displayed:

No route matches “/rails/info/properties”

This was happening because by default Passenger sets the RAILS_ENV to production. The solution was to set it to development. This can be done in a couple of ways, but I decided to add “RailsEnv development” to the Apache configuration file, inside de definition of the app’s virtual host.