Complex sentence: The line was extended the following year, reaching Hamm via Dortmund on 15 May, and, on 15 October 1847, the entire 263-kilometre-long line to Minden was completed, initially just single-tracked.
Split into simpler sentences: The line was extended the following year, reaching Hamm via Dortmund on 15 May. On 15 October 1847, the entire line to Minden was completed, initially just single-tracked.