When I saw this slide for sale on Ebay I couldn't immediately identify the "unknown station" and it seems that other's didn't either as I became the sole bidder. This is Ipswich photographed the Up platform 2 looking towards Colchester of course. The signalling was still semaphore and the small signal cabin at the London end of platforms 3/4 is visible.
In the first half of the 1990's I lived a five minute or so walk from this spot in a line roughly at the left edge of the image. The property was about halfway between this spot and Station Road which mystifies new residents as it's about half a mile from the station but the answer to the conundrum is that it refers to the first Ipswich station which was the eastern terminus of the Eastern Union Railway. Thatr was closed when the tunnel was bored and the EUR was connected to the Eastern Counties Railway on the eastern side of the hill and the present station was built.
[Mike Morant collection]