Complex sentence: The arrival of the London and Brighton Railway in 1841 brought Brighton within the reach of day-trippers from London and population growth from around 7,000 in 1801 to over 120,000 by 1901.
Split into simpler sentences: The arrival of the London and Brighton Railway in 1841 brought Brighton within the reach of day-trippers from London. The population grew from around 7,000 in 1801 to over 120,000 by 1901.