Complex sentence: The set is said to be EM 1505/ET 3505, but one other set (believed to be EM 1223/ET 3010) will also stay in New Zealand but will be scrapped.
Split into simpler sentences: The set is said to be EM 1505/ET 3505. But one other set (belived to be EM 1223/ET 3010) will also stay in New Zealand but will be scrapped.