Southern Railway routes west of Salisbury
The Southern Railway routes west of Salisbury were built by the London and South Western Railway (LSWR) and allied companies, which all became part of the Southern Railway in 1923. The railway arrived at Salisbury in 1847 but was extended westwards through the counties of Somerset, Devon and Cornwall and established an alternative to the route from London to the west built by the Great Western Railway (GWR) and its associated companies.
Source: Wikipedia — Southern Railway routes west of Salisbury (CC BY-SA 4.0)