Four important railway companies operated along the south coast of England prior to 1923 – the London & South Western Railway (LSWR), the London, Brighton and South Coast Railway (LBSCR), and the South Eastern Railway and the London Chatham and Dover Railway. (The last two had formed a working union known as the South Eastern and Chatham Railway (SECR) in 1899.) These companies were amalgamated, together with several small independently operated lines and non-working companies, to form the Southern Railway in 1923, which operated 2186 route miles (3518 km) of railway. The new railway also partly owned several joint lines, notably the East London Railway, the West London Extension Joint Railway, the Somerset and Dorset Joint Railway and the Weymouth and Portland Railway.