King’s Lynn Harbour Junction signal box was a charming little Great Eastern structure dating from c.1880. It was built just south of King’s Lynn where the two branches to South Lynn and the harbour diverged from the mainline south of the town. In this view the relatively new A47 King’s Lyn southern bypass bridge somewhat dwarfs the box that itself, after being reduced to a ground frame was closed 10.02.85. Looking at an Ordnance Survey map of the area today reveals the routes of the two branches and there is a very informative article about the area by Roger Farnworth, see….
https://rogerfarnworth.com/2018/09/16/kings-lynn-harbour-branch/