Complex sentence: The initial part of the line was between Istanbul University's Avcılar campus and Topkapı, and since then, the line has seen two extensions, the first to Zincirlikuyu and the second to Söğütlüçeşme, which is located on the Anatolian side of Istanbul.
Split into simpler sentences: The initial part of the line was between Istanbul University's Avcılar Campus and Topkapı. Since then, the line has seen two extensions, the first to Zincirlikuyu and the second to Söğütlüçeşme, which is located on the Anatolian side of Istanbul.