Complex sentence: Most of the remaining trackage (between Tampa and Bradenton) is now part of CSX Transportation's Palmetto Subdivision, with another short portion just east of Sarasota still exists as well that is now part of Seminole Gulf Railway's Matoaka branch.
Split into simpler sentences: Most of the remaining trackage (between Tampa and Bradenton) now serves as CSX Transportation's Palmetto Subdivision. Another short portion just east of Sarasota also remains that now serves as Seminole Gulf Railway's Matoaka branch.