TheGingerTrainspotter

One thing I'm trying to work out- The wagons in most of the photos I've seen are marked as internal use only- Given that, where would they be taken within the harbour? I'm assuming that the coal was loaded into these wagons somewhere within the docks, since they can't travel on the main line. Where in the harbour would these wagons have been taken?

Looking for some information and photos of this little line. Found a bit online but it's not much, Are there any books or editorials that cover this railway in any great detail?