why does Newhaven have three stations?
It seems odd the station now best served by the harbour is the one without anything sea related in its name Newhaven Town
Presumably the harbour has downsized over the years... never been on the Seaford branch
Yes, the harbour was once full of rail served quay sides and sidings. Marine station was right next to where the cross channel ships loaded (it still is), so you would go straight out the doors and onto the ship. However, it was a terminal station, so harbour served the area as well, as well a an industrial area, but was served by trains to and from Seaford. Town was closer to the bridge and thus the town centre over the river/port. These days ferries are all about HGV and car traffic. So you need long storage/wating/holding areas. So folks get off at town, walk to the terminal, then the holding areas are along the line to Harbour station, and then the ferry waits till just outside of Marine. What few foot punters are bused from the terminal to the ferry.
Google maps show the situation quite well.