In 1999, the S8 was effectively divided into two lines, the S8 and S9, both of which travel between Hanau and Wiesbaden via Bischofsheim. The S8 continues to travel through the centre of Mainz, while the S9 travels via Mainz-Kastel. This arrangement means that it is possible to travel between Wiesbaden, the capital of the state of Hesse, and Frankfurt, the state's largest city, by three different routes. In the same year, a new station on lines S3-S6 was opened in the Frankfurt fairground (Frankfurt Messe station).