I recently observed a company move from 'everyone is the same title' to specific jnr, snr, distinguished engineer titles. The primary reasons for this was to create a framework for salaries and provide a defined track for 'progressing' as the organisation got bigger.
But if you think about it - it really comes down to a method of retaining staff and salary banding, I have yet to see any organisations where the titles of engineers defines their abilities, all engineers have the same say.