Complex sentence: At the same time, the elevated 4-track section from Nerima-Takanodai to Nakamurabashi opened, and this elevated 4-track section was extended to Nerima in 2003.
Split into simpler sentences: At the same time, the elevated 4-track section from Nerima-Takanodai to Nakamurabashi opened. This elevated 4-track section was extended to Nerima in 2003.