Hamworthy station was originally Poole Junction and the Hamworthy Junction before becoming Hamworthy station in the 2000's.
The track plan of the Hamworthy branch can be deduced from countless photographs taken by the RAF (and German "tourists") from the air dating from the 1930's, 1940's, 1950's and 1960's. These can be found in countless books on the history of Poole and one I have includes the old Poole station on the Hamworthy side of Poole Quay, including the opening ceremony. This had an unplanned incident when one of the 6 wheeled carriages derailed during shunting on the newly laid track and had to be jacked back onto the rails again as the ceremony progressed.
The line has quite an interesting and complicated trackplan with plenty of pointwork before the 1990's, most of it old LSWR.
It was originally a double track mainline and the end of the line for that part of the "Corkscrew" line, with a mainline junction at Poole (Hamworthy) Junction to Weymouth and Dorchester. In the 1860's a causeway was built across Holes Bay into Poole to link with a new Poole goods yard (still no station at that time) and a tramway built to the Poole side of the Quay. The tramway was serviced by LSWR B4 0-4-0T tank locomotives "Normandy" and "Le Harve" which also performed the local pick up goods routes on the Hamworthy branch line and surrounding station sidings around the "triangle", collecting and returning wagons to Poole goods yard. They continued in this role until the last days of steam when they were replaced by Drewrey 0-6-0 diesel machanical shunting engines.
In 1872 a line was built to the new town and resort of Bournemouth which ended in a Terminus at what was Bournemouth West station. The first Poole Town station in the actual town appeared at this time and the double track branch into Poole for the goods yard became a passenger mainline. Poole Terminus on the quay closed for passenger traffic shortly afterwards, being retained only for parcels and freight. In the late 1950's one of the double track road bridges over Lake Road was removed as was the double track line from there to Hamworthy Junction. The other side of the road bridge was still serving J R Smiths steel suppliers so the double track was narrowed into a single line with a point to create a mile long passing loop.
The Bath to Bournemouth West via Poole Town station mainline is more famously remembered for being the Somerset & Dorset Joint Railway mainline route.
Poole Junction was renamed Hamworthy Junction to prevent confusion and was a double junction at this time. Poole Town became just Poole station.
Doctor Beeching's axe saw the main line from Hamworthy Junction to Wimborne, Ringwood and Brockenhurst, which previously allowed passengers to travel from Hamworthy to Swanage, Blandford, etc. with ease.
As an exhibition layout with lots of action, perhaps modelling Hamworthy in its Hamworthy Junction or Poole Junction days, before Doctor Beeching, would make a more adventurous project with a way junction with 4 seperate fiddle yards feeding trains through the junction in various directions through the original 4 tracks (3 platform touching) that were once there.
Nowadays Hamworthy station is a mere shadow of what it once was.