Complex sentence: The central part of the line is in a tunnel (2310 m long), it then crosses the Vistula by a bridge (445 m) located between Poniatowski Bridge and Świętokrzyski Bridge.
Split into simpler sentences: The central part of the line is in a tunnel, which 2.31km long. It then crosses the Vistula by a bridge (445 m) located between Poniatowski Bridge and Świętokrzyski Bridge.