Why do some stations have the state names or other regional names as suffixes? E.g., Chandrapur (Maharashtra) or Srirampur (Assam)?

This is done when there may be other towns of the same name elsewhere that may perhaps be as prominent or even better known than the station in question. Adding the state name as a suffix helps to disambiguate the station from the other towns of the same name. E.g., Berhampur (West Bengal) and Berhampur (Orissa). Hyderabad station is often referred to in older documents as Hyderabad Deccan, to distinguish it from the other Hyderabad of British India (in Sindh, now in Pakistan). Similarly, there are Hingoli Deccan (to distinguish the better-known one from the one in Rajasthan) and Kohir Deccan.

Source - IFRCA.org