Complex sentence: The advent of WWI created a need for high quality coal to fuel US battleships and by 1917 the US Navy had constructed rail from the port of Seward to the Chickaloon coal deposits.
Split into simpler sentences: The advent of WWI created a need for high quality coal to fuel US battleships. By 1917 the US Navy had constructed rail from the port of Seward to the Chickaloon coal deposits.