"Town" suffix used in stations - Old times that place has nearby 2 or more stations with same name in which one station is underlying in town area and others are in 15 - 20 Km. proximity, so identify that station railway used town suffix. Like Malda Town, Dibrugarh Town, Kakinada Town, Etc.
"Road" suffix used in stations - When there is no rail connectivity to that particular highlighted useful place, nearest rail head where you can find road transport easily and station is road side or close proximity...
more... to road situated. For useful of passengers railway used road suffix to tell this is nearest point to connect with that place. Like Abu Road, Garhwa Road, Gevra Road, Etc.
"New" suffix used in stations - Not much idea about it. But nowdays we are witnessed DFCs there they are using New Ateli, New Phulera, New Khurja, New Bhadan, Etc. to identify stations.
"Central" suffix used in stations -These types of stations are Big, Renowned, Main Railway Stations in there route. These stations have direct rail connectivity to all zonal headquarters. This is used by British & American to identify. Currently India Have 5 suffix Central Stations - 1. Kanpur Central, Mumbai Central, Managlore Central, Thiruvananthapuram Central & Chennai Central.
Hope this information is helpful to you.