Simplify the following text for a Grade 12 native English-speaking person.
Original: The railway was formed by the amalgamation of several smaller railway companies , the largest of which were the London & South Western Railway ( LSWR ) , the London , Brighton and South Coast Railway ( LBSC ) and the South Eastern and Chatham Railway ( SECR ) .
Simplified: The railway was formed by the amalgamation of smaller companies , the largest of which were the London & South Western Railway , the London , Brighton and South Coast Railway , and the South Eastern and Chatham Railway .