Somerset & Dorset Joint Railway
From N Gauge wiki
The Somerset & Dorset Joint Railway existed in several guises between 1854 and final closure to passenger services in 1966.
It started off as two separate companies, the Somerset Central Railway which began service in 1854 and the Dorset Central Railway which began in 1860. These two companies agreed from a very early date to join together both their tracks and their companies, with the result that the Somerset & Dorset Railway was born in 1862. (ref Peter Kessler, 2013)