What cities does the train from Xi 'an to Yanzhou pass through?

That depends on which train to take. The following is the route of K 1028/K 1025, and everything else is similar.

Passing through Xi, Weinan, Huashan and Lingbao? Sanmenxia west, Sanmenxia? Luoyang, Zhengzhou? , Lankao? Shangqiu, Yucheng County? , Xiayi County? Lushan mountain? Xuzhou? , Zaozhuang West? Tengzhou? , Yanzhou.