The protest was organised by All India Confederation of SC/ST Organisations at Jantar Mantar.
A R Joshi, chief patron of the Confederation, said they were sending a memorandum to President Pratibha Patil and Prime Minister Manmohan Singh.
"If we do not get positive response from them, then we'll intensify our struggle," he said.
Acting Chairman of the Confederation and representative of the All India SC/ST Railway Employees Association, Ashok Kumar said they demand reservation not only in promotions but elsewhere also where none exist.
The protesters also demanded that the reservation be provided in private sector, higher education and judiciary.
