What is difference between TT and TC te

TTE = Travelling ticket examiner {Indian railways}

TC= Ticket collector {Indian railways}

• Ticket Collector, TC check passengers for valid tickets and fine ticket-less travelers. They are posted on platforms. They can be with or without uniforms (a Black Coat), but they must carry a badge and Id Card with them.
• On the other hand Train Ticket Examiner, TTE ensure that seats are rightly allotted to passengers with reservations, and fine ticket-less travelers in the train. They are posted on the running trains. They are always in uniform and have the reservation charts with them. They too have to carry a badge and Id Card with them on duty.