Complex sentence: The last KT4s ever produced were delivered to Belgrade in 1997, these tramcars were equipped with IGBT-modules and recouperative braking and named KT4M-YUB (where B stands for Belgrade to be distinguished from Zagreb model).
Split into simpler sentences: The last KT4s ever produced were delivered to Belgrade in 1997. Those tramcars were equipped with IGBT modules and recouperative braking and named KT4M-YUB (where B stands for Belgrade to be distinguished from Zagreb model).