Fix coherence of the sentence: Complicating the journey, however, was Grierson's Raid, which rendered unusable portions of the railroad east of Jackson and about 50 miles (80 km) of track south of Brookhaven, Mississippi.
Which complicating the journey, however, was Grierson's Raid. Which rendered unusable portions of the railroad east of Jackson and about 50 miles (80 km) of track south of Brookhaven, Mississippi.