Complex sentence: These routes survived the 1923 amalgamation, when all became part of the London, Midland and Scottish Railway; but under British Railways both were subsequently closed in the 1950s, and Bradley station itself closed in 1950.
Split into simpler sentences: These routes survived the 1923 amalgamation, when all became part of the London, Midland and Scottish Railway. However, under British Railways both were subsequently closed in the 1950s, and Bradley station itself closed in 1950.