Complex sentence: In 1996, the TTC overhauled its rapid transit route numbers and stopped trying to market the Harbourfront route as'rapid transit' changing the number to 510; the tracks were later extended in two directions to form the 510 Spadina and 509 Harbourfront routes.
Split into simpler sentences: In 1996, the TTC overhauled its rapid transit route numbers and stopped trying to market the Harbourfront route as'rapid transit'. The tracks were later extended in two directions to form the 510 Spadina and 509 Harbourfront routes.